Grey Matter
-Unmyelinated neurons; Dendrites
-Cluster of cell bodies in the CNS are called Nuclei
White Matter
-Myelinated axons
-Axon bundles connecting CNS regions are Tracts
CNS Protection
Brian = Bony Cranium and Meninges
Spinal Cord = Vertebral Column
Meninges (IN ORDER)
Dura Mater
Arachnoid Mater
Pia Mater
(DAP)
Spinal Cord Parts
Butterfly shape = Grey Matter
Rest = White Matter
What is grey matter in the spinal cord made of?
Interneurons, Cell bodies of Efferent Neurons (anterior horn) & the axon terminals of Afferent Neurons (Posterior horn)
What is white matter in the spinal cord made of?
Groups of myelinated axons (ascending or descending tracts)
How are white matter tracts organized for MOTOR information?
Descending Tracts
How are white matter tracts organized for SENSORY information?
Ascending Tracts
What forms the Choroid Plexus?
Ependymal Cells and a Network of capillaries
Ventricles of the Brain
2 Lateral Ventricles connected to the 3rd and 4th ventricles & extend to the central canal of SC
What happens in the Arachnoid Villi?
CSF returns to blood circulation
AS LONG AS CSF IS LESS THAN VENOUS PRESSURE
What percent of blood is received by the brain?
15%
Parts of the Forebrain
Cerebrum and Diencephalon
Parts of the Brainstem
Midbrain, Pons, and Medulla Oblongata
Somatosensory
Ascending Tracts - SENSORY
Corticospinal
Descending Tracts - Motor
Pyramids
Area of Neuron Crossover
What does the Medulla control?
Cardiovascular centers (blood pressure, HR), Reparatory centers, swallowing, and vomiting reflex
What do the Pons control?
Coordinates control of breathing, Urination reflexes
What does the Midbrain control?
Reflexive eye movement; Tracts
Lower Brain TO Higher Brain
Where is the Substantia nigra?
Midbrain
What does the Substantia nigra control?
Suppress unwanted muscle tremor
What is the Substantia nigra?
Group of neurons that release dopamine
Reticular Formation
Site where general anesthetics work
What does the Reticular Formation control?
Maintain consciousness, Pain Modulation, and Arousal
What are cranial nerves 1 and 2?
PURELY SENSORY
Cranial Nerve 3
Oculomotor
What does the Oculomotor Nerve control?
Lens and pupils - eye reflex
Cranial Nerve 7
Facial Nerve
What does the Facial Nerve control?
Tear and salivary glands
Change facial expressions - facial muscles
Cranial Nerve 9
Glossopharyngeal
What does the Glossopharyngeal Nerve control?
Salivary glands and BP sensor
Muscles for swallowing
Cranial Nerve 10
Vagus Nerve
What does the Vagus Nerve do?
Digestive organs, heart Regulate HR, and Innervate airways
Voice and swallowing muscles
Where are the Vagus and Glossopharyngeal Nerves?
MEDULLA
Where is the Facial nerve?
PONS
Where is the Oculomotor nerve?
MIDBRAIN
What does the Diencephalon consist of?
Thalamus, Pineal Gland, and Hypothalamus
Thalamus
a collection of several nuclei that serve as relay stations for sensory information to go to CEREBRAL CORTEX
What does the Pineal Gland do?
Neurosensory cells that produce MELATONIN
What does Melatonin do?
regulates Sleep - Wake cycles, Activates reproductive, Initiates puberty time, and WBC - increase immune system
What is the Hypothalamus connected to?
Pituitary Gland
What is the major regulator of the bodies homeostasis?
Hypothalamus
What does the Hypothalamus control?
Eating Behavior, Thirst Centers, Temperature Regulation, Circadian Clocks, Links Memory centers of the Brain, and Emotional Centers such as Rage and Aggression; Libido
Hypothalamus produces what?
Hormones: Oxytocin and ADH
Posterior Pituitary
Extension of the brain that secretes neurohormones made in the hypothalamus
What does the cerebellum control?
Coordinates balance/posture
What makes up about 85 percent of the mass in the brain in human beans?
Cerebrum
basal ganglia
Very complex pattern of feedback between different areas of the brain for controlled motor patterns
Cerebral cortex General Functions
Intelligent thought, motor control, sensory perception, math, artistic, planning, judgement
Broca's area
Motor control of speech patterns
Prefrontal lobe
judgement/inhibitions
Frontal Lobe
Motor control centers (voluntary) (motor cortex)
Parietal Lobe
Somatosensory areas (from skin, viscera)
Occipital Lobe
Vision processing
Temporal Lobe
Auditory processing
Wernicke's area
Language comprehension
Proprioception / Special senses
Nerve endings for sensations of touch, temperature, itch, pain
Simple Receptors
Stimulus actives FREE NERVE ENDINGS --> then to unmyelinated or myelinated axon
Complex Neural Receptors
Nerve endings enclosed in connective tissue ENCLOSED NERVE ENDING --> MYELINATED axon
Special Senses Receptors
Cells that release neurotransmitter onto sensory neurons to excite
Specialized receptor cell ---> MYELINATED Axon
Muscle Spindles
buried among the fibers of the muscle
NERVE ENDING FOR Proprioception
Somatic Motor Neurons
Control Skeletal Muscle contraction
Generally voluntary; some reflex
Autonomic Neurons
Control Glands, Smooth muscles, Cardiac Muscles
Involuntary
2 Divisions: Parasympathetic and Sympathetic
What is the Cardiovascular center controlled by?
Medulla
Hypothalamus Sensors signal what?
PAIN
Cerebral / Limbic System Signals what?
Sweat glands
Ex: something scary
Autonomic pathways consist of....
2 neurons that synapse in an autonomic ganglion
In 2 Efferent Neurons in Series, what happens?
2 neurons that synapse in an autonomic ganglion
2 Efferent Neurons in Series - 1st Neuron is?
PREganglionic
2 Efferent Neurons in Series - 2nd Neuron is?
POSTganglionic
What type of neurotransmitter is ALWAYS released from PREganglionic?
Acetylcholine
What type of neurotransmitter is MOSTLY released from PREganglionic?
Nicotinic
What are the 3 Differences in ANS Divisions? (Parasympathetic & Sympathetic)
1. Different points of origin of neurons
2. Different Location of Autonomic Ganglia
3. Difference in Neurotransmitters & Receptors
What are the different points of origin of neurons in the CNS? (Parasympathetic & Sympathetic)
Parasympathetic = Brain Stem and Sacral Region of SC
Sympathetic = Thoracic and Lumbar Region of SC
What are the different Locations of Autonomic Ganglia? (Parasympathetic & Sympathetic)
Parasympathetic = Near effector tissue
Sympathetic = 2 ganglion chains along either side of the vertebral column
What is the difference in Neurotransmitters & Receptors in
Parasympathetic & Sympathetic
Parasympathetic = Postganglionic are CHOLINERGIC - Releases Ach - binds to cholinergic receptors
Sympathetic = Postganglionic are ADRENERGIC - Releases Norepinephrine - binds to adrenergic receptors
What is the exception of the 2-Neuron Chain?
There is DIRECT INNERVATION of Adrenal Medulla by SNS to stimulate EPINEPHRINE secretion into blood --> BINDS TO ADRENERGIC BETA 2 RECEPTOR
Catecholamines
Acetyl group with one chemical change... some type of group added to it
Adrenal Cortex surrounds....
Adrenal Medulla
Adrenal Cortex
True endocrine gland
Adrenal Medulla
Modified sympathetic ganglion
Sympathetic Nervous System has what kind of situations?
'E Situations' - Emergency, Emotional, Exercise
How does the SNS effect the airways?
smooth muscle RELAXES - action: through epinephrine BEING RELEASED and binding to Beta2 receptors
How does the PNS effect the airways?
smooth muscle CONSTRICTS
What is special about the Adrenal Medulla?
only ONE neuron chain - results in epinephrine being released as hormone into blood - epinephrine acts like NorEPI, just last longer - PROLONGS RESPONSE
What happens when Norepinephrine is released onto a blood vessel and binds to an ALPHA receptor?
VASOCONSTRICTION ---> INCREASE BP
What happens when Norepinephrine is released onto a blood vessel and binds to an BETA receptor?
(also happens on skeletal muscle)
VASODILATION --> INCREASE BLOOD FLOW TO ORGANS
Neuroeffector Junction
The synapse between a POSTganglionic autonomic neuron and its target cells
VARIOSITES
series of swollen areas at their distal ends of neurons containing Neurotransmitters - Like a beaded chain - more widespread than a neuron signaling another neuron
Control of target by modulating the concentration of neurotransmitter in the synapse
Diffuses away, Metabolized by enzymes in the ECF, and Reuptake and degradation by Monoamine Oxidase
What happens in Somatic Motor Neurons? [OVERVIEW]
Excitatory of skeletal muscles, mostly voluntary, Single myelinated neuron from CNS to skeletal muscles, and Acetylcholine is released and binds to Nicotinic Receptors
Neuromuscular Junction
Consists of axon terminals and MOTOR END PLATE on the muscle
Membrane is HIGHLY FOLDED
What kind of receptor is found on parasympathetic target cells?
Cholinergic Receptor
Synaptic Cleft at Neuromuscular Junction
The Cholinergic Nicotinic Ach Receptor binds 2 Ach Molecules, opening cation channel for Net Na+ INFLUX --> depolarized the muscle fiber
Skeletal Muscle
muscle cylinders = muscle fibers = muscle cells that fuse together and form cylinder shape
*
STRIATED
*
Cardiac Muscle
muscle cylinders = muscle fibers = muscle cells that fuse together and form cylinder shape, BUT IS HIGHLY BRANCHED
*
STRIATED - centrally located nuclei
*
Intercalated Disk
Where GAP JUNCTIONS are located IN BETWEEN EACH MUSCLE
Smooth Muscle
NOT STRIATED
-Most part = single cells that function together as one unit
Muscle Cells that are fused together are called....
Muscle Fibers
Hypertrophy
Muscles grow by size
Fascicles
Bundled fibers surrounded by connective tissue
Epimysium
Connective tissue surrounding ALL fascicles in muscle - WRAPPING UP ALL THE FASICLES
Endomysium
Connective tissue around muscle fibers
Structure of Muscle Fibers
Sarcolemma, Sarcoplasm, Sarcoplasmic Reticulum, T-Tubules, and Myofibrils`
Sarcolemma
Cell Membrane
Sarcoplasm
Cytoplasm (with # of mitochondria, Glycogen, and Myoglobin)
Sarcoplasmic Reticulum
Endoplasmic reticulum, Stores Ca2+
Transverse Tubules (T-Tubule)
Connected with Sarcolemma
Myofibrils
Contractile structures made of thick and thin filaments
What is a thin filament of a myofibril made of?
Myosin
What is a thick filament of a myofibril made of?
Actin
What is myosin
A motor protein that has intertwined tails, a moveable hinge region, and the head region
What does the Myosin Head Region do?
-Acts as an enzyme With ATPase activity
-HYDROLIZIES ATP
-Actin binding site
What proteins are associated with thin filament?
Troponin and Tropomyosin
Cross - Bridge
Myosin Head binds Actin
Troponin is made of....
3 Protein Subunits
Tropomyosin
Covers sites at rest
Why is Tropomyosin elevated during a heart attack?
The muscle is literally torn and broken open, thus tropomyosin is then released into blood
Dystrophin
helps anchor to sarcolemma
Titin
The largest protein in the body
What happens when someone has Muscular Dystrophy?
PROBLEMS WITH DYSTROPHIN, which helps anchor to carcolemma
What happens to the sarcomere during contraction?
It shortens
Neuromuscular Junction Signaling
Motor Neuron releases Ach -> Bind to nicotinic AchR ->AP generated
Excitation-Contraction Coupling
AP conducted across Sarcolemma -> Opens Voltage- Gated Ca2+ channels on Sarcoplasmic Reticulum -> intracellular Ca2+ levels increased
Sliding Filament Theory
Ca2+ binds TROPONIN -> Actin - Myosin CROSSBRIDGE formation -> Power Stroke of Myosin Heads
SLIDING FILAMENT THEORY STEPS
When CALCIUM levels are elevated in sarcoplasm:
-Calcium binds Troponin C -->
-Tropomyosin moves away from actin to expose myosin-binding sites on actin -->
-Myosin HEADS binds tightly to actin - (FORMS A CROSSBRDIGE)
-POWER STROKE = movement of myosin he
The Contraction Cycle - occurs before calcium binds
-ATP binds to Myosin and is HYDROLYZED
-ADP and P remain bound to myosin head
-Myosin head is in position
-Upon binding of Actin with high affinity, Phosphate is released & Power Stroke occurs
*
POWER STROKE
* = movement of myosin heads
Rigor State
High affinity & high force binding between Actin and Myosin UNTIL NEW ATP PRESENT
What happens to Ach that was released?
Broken down by Achesterase or diffused away
Where does the cell get ATP from?
MITOCHONDRIA and AEROBIC RESPIRATION
Metabolic Pathways to Obtain Energy (3)
Creatine phosphate, Anaerobic Glycolysis, and Aerobic Respiration
Creatine phosphate
Short acting; donates Phosphate group to ADP to replenish ATP
Hypertrophy
INCREASE muscle size (high thick/thin filaments)
Where does Creatine go?
Excreted through urine as a waste product
Anaerobic Glycolysis
Glucose --> Pyruvate
-Rapid, No O2 needed; lactic acid can be generated; small amount of ATP synthesized
Aerobic Respiration
In mitochondria; slower, REQUIRES O2, large amount of ATP Synthesized
How is the heart positioned?
In Mediastinum of Thoracic Cavity
How is the Apex of the heart positioned?
Toward 5th intercostal space of ribs
What is the heart encased in?
Pericardium membrane
Pericardium
Double-layer serous membrane filled with ~25ml fluid in cavity to reduce friction - lubrication - reduce inflammation, pain, and friction
What are the layers of the Pericardium?
-Outermost layer - Parietal Laver
-Innermost layer - Visceral Layer - connected directly to heart
3 Layers of the Heart Wall
Epicardium, Myocardium, and Endocardium
Epicardium
Outermost Layer/ Superficial Layer
*
SAME THING AS VISCERAL LAYER
*
Myocardium
Most of heart wall - cardiac muscle
Endocardium
Inner lining of thin layer of simple exchange epithelium
Describe Contractile Cells
Branched, have a single nucleus, and are joined by junctions known as INTERCALATED DISCKS with GAP JUNCTIONS
Myocardium has what kind of arrangement?
Spiral
Where does the Aorta pump blood to?
Blood to the BODY
Where does the Pulmonary trunk pump blood to?
Blood to the LUNGS
What are special muscle projections in the heart?
Papillary muscles
What do Papillary Muscles do? What do they look like?
Cone shaped muscles that are attached to chordae tendineae that are then connected to valves
Right AV Valve is what kind of valve?
TRICUPSID VALVE
Left AV Valve is what kind of valve?
BICUPSID VALVE ; Mitral Valve
Why do the valves of the heart open?
Due to differences in pressures between chambers
What happens when pressure to valves is greater than ventricles?
AV Valves open and blood flows into ventricles
How are the AV Valves attached?
to CORD - LIKE TENDONS that connect to bands of PAPILLARY MUSCLES
Where are the Semilunar Valves?
At the base of the large arteries from heart
What side is the Aortic Semilunar Valve on?
LEFT
What side is the Pulmonic Semilunar Valve on?
RIGHT
When do semilunar valves open?
When there is a pressure differences between ventricles and blood vessels
When do semilunar valves open?
When pressure on ventricle greater than in blood vessel
When do semilunar valves close?
When blood ejected into blood vessel
What do right and Left coronary arteries do?
Supply oxygenated blood to heart
What is Distal to the Aortic Semilunar valve?
An opening to CORONARY ARTERIES
What is the Interventricular Septum is made up of?
Fibrous connective tissue skeleton
OVERVIEW OF SEMILUNAR VALVE??
The Semilunar Valve prevents blood that has been ejected into the arteries from flowing back into the ventricles during ventricular relaxation
Valve Disorders (2)
Stenosis and Regurgitation
Stenosis
Opening is too Narrow
Regurgitation
Valves don't close completely - flow backwards
2 Types of Cells Contribute to Heart Pumping
Contractile Cells (Cardiomyocytes) AND Autorhythmic Cells (Nodal Cells)
Contractile Cells (Cardiomyocytes)
Organized into sarcomeres ; T-Tubules, and Sarcoplasmic reticulum (stores calcium)
Autorhythmic Cells (Nodal Cells)
Smaller, without organized sarcomeres & Spontaneous generation of AP's
General Mechanisms of Cardiac Myocyte Contraction
-Action Potential Initiates
-Voltage change leads to increased intracellular Ca2+
-Ca2+ binds to Troponin on thing filament to initiate Sliding Filament for contraction
-Relaxation when Ca2+ leaves lowered in cytoplasm
What makes sodium start to enter a skeletal muscle?
-EXCITATION
-STIMULATED BY SOMATIC MOTOR NEURONS
-RELEASES ACETYLCHOLINE
-BINDING TO NICOTINIC ACEYTLCHOLINE RECEPTORS
-SODIUM STARTS FLOWING IN (INFLUX)
-LIGAND GATED Ach
-REACHES THRESHOLD - JUST THE ELECTRICAL PART OF THINGS
-OPENS VOLTAGE - GATED ION
EXCITATION CONTRACTION COUPLING [OVERVIEW]
-ACTION POTENTIAL CONDUCED DOWN T-TUBULES TO CHANGE VOLTAGE
-CHANGE OF VOLTAGE DETECTED BY DHP
-OPENING OF RYANIDINE RECEPTORS ON ENDOPLASMIC RETICULUM
-THEN CALCIUM RELEASES
-THEN CONTRACTION - SLIDING FILAMENT
CARDIAC MUSCLE [OVERVIEW]
-STIMULATED BY ELECTRICAL CELLS THAT MAKE ACTION POTENTIALS
STILL NEED DETAILS
-CAUSES MUSCLE CELLS TO HAVE ACTION POTENTIAL
-STARTS AT REST AND WHEN AP GETS TO HEART MUSCLE CELLS, IT WILL OPEN WHEN THE AP GETS THERE --> OPENS SODIUM CHANNEL = DEPOLARIZAT
Action Potential Curve for Cardiac Muscles (Phases)
0. Na 'fast' channels open = DEPOLARIZATION
1. K+ channel transiently open; Na+ channels close
2. Ca2+ Channels OPEN; PLATEU
3. Slow K+ Channels Open; Ca2+ channels close = REPOLARIZATION
4. Resting Membrane Potential
Excitation - Contraction Coupling in Cardiac Muscle
STEPS:
1. AP is signaled in Cardiac Muscle (initiated by Nodal Cells - spontaneously generated)
2. Opens L-Type Ca2+ Channels on T-Tubules --> Ca2+ Enters from ECF** - now the trigger
1. L-Type for LONG
3. Ca2+ opens Ryanodine Receptor on SR (sarcoplasmic reticu
How does Excitation - Contraction Coupling SHUT OFF:
7. Ca2+ unbound from Troponin
8. Ca2+ - ATPase pumps Ca2+ back into SR
A. CANT PUMP CALCIUM OUT WITHOUT ATP
9. ALSO, Ca2+ out of cell thru Na+ / Ca2+ Exchanger
A. ESTABLISHES LOCAL GRADIENT
10. Na+ - K+ ATPase drives counter-transport
SNS Effects Contractility - more force = more blood ejected: NEpi binding to Beta 1 receptor (adrenergic receptor) WHICH LEADS TO?
INCREASE CONTRACTILE FORCE (Inotropy)
--> Increased Ca2+ Influx via VOLTAGE - GATED Ca2+ Channel
(L Type Channel on Membrane)
Excitation of heart initiated by Sinoatrial (SA) Nodal Cells (In right atrium wall) involves what?
-ALL CARDIAC MUSCLE CELLS
-Spontaneously make Action Potentials
-Electrical current between cells from cardiac cells to muscle cells
How do Nodal cells differ from Contractile cells?
-RMP less negative (-60mV) = *
CLOSER TO THRESHOLD --> DEPOLARIZATION
*
-Cells constantly permeable to Na+ at "rest" thru Na+ Leak Channels (Pacemaker potential)
What do Nodal Cells do AT THRESHOLD?
-Voltage-gated Ca2+ Channels OPEN for Depolarization
-Followed by opening of Voltage-gated K+ Channels for Repolarization
Pathway of Excitation through the Heart [not explaining]
1. SA Node
2. Internodal Pathway
3.Atrioventricular Node
4.AV Bundle
5. Right & Left Bundle Branch
6. Purkinje Fibers
Pathway of Excitation through the Heart [explaining]
� Signal initiated in the SA Node
� AP travels through internodal tracts to the AV Node
? Signal delayed ~0.1 seconds in AV Node
� And Signals Atrial Muscle --> followed by Atrial Contraction
� AP travels through AV Bundles & down IV Septum through the R/
What happens when the Atrial Muscle Contracts?
Remaining blood flows to the Ventricles
What happens when the ventricles contract?
Blood exits through large arteries
WHAT NERVE ACTS ON PARASYMPATHETIC NERVE SLOWS DOWN Heart Rate?
VAGUS NERVE - CARNIAL NERVE 10
Where is Epinephrine (ADRENALINE) PRODUCED?
Adrenal Medulla
Rest-and-Digest
Parasympathetic Division
Fight-or-Flight
Sympathetic Division
What does the Phrenic Nerve innervate?
Thoracic - Diaphragm
Grey Matter
-Unmyelinated neurons; Dendrites
-Cluster of cell bodies in the CNS are called Nuclei
White Matter
#NAME?
CNS Protection
Brian = Bony Cranium and Meninges
Spinal Cord = Vertebral Column
Meninges (IN ORDER)
Dura Mater
Arachnoid Mater
Pia Mater
(DAP)
Spinal Cord Parts
Butterfly shape = Grey Matter
Rest = White Matter
What is grey matter in the spinal cord made of?
Interneurons, Cell bodies of Efferent Neurons (anterior horn) & the axon terminals of Afferent Neurons (Posterior horn)
What is white matter in the spinal cord made of?
Groups of myelinated axons (ascending or descending tracts)
How are white matter tracts organized for MOTOR information?
Descending Tracts
How are white matter tracts organized for SENSORY information?
Ascending Tracts
What forms the Choroid Plexus?
Ependymal Cells and a Network of capillaries
Ventricles of the Brain
2 Lateral Ventricles connected to the 3rd and 4th ventricles & extend to the central canal of SC
What happens in the Arachnoid Villi?
CSF returns to blood circulation
AS LONG AS CSF IS LESS THAN VENOUS PRESSURE
What percent of blood is received by the brain?
15%
Parts of the Forebrain
Cerebrum and Diencephalon
Parts of the Brainstem
Midbrain, Pons, and Medulla Oblongata
Somatosensory
Ascending Tracts - SENSORY
Corticospinal
Descending Tracts - Motor
Pyramids
Area of Neuron Crossover
What does the Medulla control?
Cardiovascular centers (blood pressure, HR), Reparatory centers, swallowing, and vomiting reflex
What do the Pons control?
Coordinates control of breathing, Urination reflexes
What does the Midbrain control?
Reflexive eye movement; Tracts
Lower Brain TO Higher Brain
Where is the Substantia nigra?
Midbrain
What does the Substantia nigra control?
Suppress unwanted muscle tremor
What is the Substantia nigra?
Group of neurons that release dopamine
Reticular Formation
Site where general anesthetics work
What does the Reticular Formation control?
Maintain consciousness, Pain Modulation, and Arousal
What are cranial nerves 1 and 2?
PURELY SENSORY
Cranial Nerve 3
Oculomotor
What does the Oculomotor Nerve control?
Lens and pupils - eye reflex
Cranial Nerve 7
Facial Nerve
What does the Facial Nerve control?
Tear and salivary glands
Change facial expressions - facial muscles
Cranial Nerve 9
Glossopharyngeal
What does the Glossopharyngeal Nerve control?
Salivary glands and BP sensor
Muscles for swallowing
Cranial Nerve 10
Vagus Nerve
What does the Vagus Nerve do?
Digestive organs, heart Regulate HR, and Innervate airways
Voice and swallowing muscles
Where are the Vagus and Glossopharyngeal Nerves?
MEDULLA
Where is the Facial nerve?
PONS
Where is the Oculomotor nerve?
MIDBRAIN
What does the Diencephalon consist of?
Thalamus, Pineal Gland, and Hypothalamus
Thalamus
a collection of several nuclei that serve as relay stations for sensory information to go to CEREBRAL CORTEX
What does the Pineal Gland do?
Neurosensory cells that produce MELATONIN
What does Melatonin do?
regulates Sleep - Wake cycles, Activates reproductive, Initiates puberty time, and WBC - increase immune system
What is the Hypothalamus connected to?
Pituitary Gland
What is the major regulator of the bodies homeostasis?
Hypothalamus
What does the Hypothalamus control?
Eating Behavior, Thirst Centers, Temperature Regulation, Circadian Clocks, Links Memory centers of the Brain, and Emotional Centers such as Rage and Aggression; Libido
Hypothalamus produces what?
Hormones: Oxytocin and ADH
Posterior Pituitary
Extension of the brain that secretes neurohormones made in the hypothalamus
What does the cerebellum control?
Coordinates balance/posture
What makes up about 85 percent of the mass in the brain in human beans?
Cerebrum
basal ganglia
Very complex pattern of feedback between different areas of the brain for controlled motor patterns
Cerebral cortex General Functions
Intelligent thought, motor control, sensory perception, math, artistic, planning, judgement
Broca's area
Motor control of speech patterns
Prefrontal lobe
judgement/inhibitions
Frontal Lobe
Motor control centers (voluntary) (motor cortex)
Parietal Lobe
Somatosensory areas (from skin, viscera)
Occipital Lobe
Vision processing
Temporal Lobe
Auditory processing
Wernicke's area
Language comprehension
Proprioception / Special senses
Nerve endings for sensations of touch, temperature, itch, pain
Simple Receptors
Stimulus actives FREE NERVE ENDINGS --> then to unmyelinated or myelinated axon
Complex Neural Receptors
Nerve endings enclosed in connective tissue ENCLOSED NERVE ENDING --> MYELINATED axon
Special Senses Receptors
Cells that release neurotransmitter onto sensory neurons to excite
Specialized receptor cell ---> MYELINATED Axon
Muscle Spindles
buried among the fibers of the muscle
NERVE ENDING FOR Proprioception
Somatic Motor Neurons
Control Skeletal Muscle contraction
Generally voluntary; some reflex
Autonomic Neurons
Control Glands, Smooth muscles, Cardiac Muscles
Involuntary
2 Divisions: Parasympathetic and Sympathetic
What is the Cardiovascular center controlled by?
Medulla
Hypothalamus Sensors signal what?
PAIN
Cerebral / Limbic System Signals what?
Sweat glands
Ex: something scary
Autonomic pathways consist of....
2 neurons that synapse in an autonomic ganglion
In 2 Efferent Neurons in Series, what happens?
2 neurons that synapse in an autonomic ganglion
2 Efferent Neurons in Series - 1st Neuron is?
PREganglionic
2 Efferent Neurons in Series - 2nd Neuron is?
POSTganglionic
What type of neurotransmitter is ALWAYS released from PREganglionic?
Acetylcholine
What type of neurotransmitter is MOSTLY released from PREganglionic?
Nicotinic
What are the 3 Differences in ANS Divisions? (Parasympathetic & Sympathetic)
1. Different points of origin of neurons
2. Different Location of Autonomic Ganglia
3. Difference in Neurotransmitters & Receptors
What are the different points of origin of neurons in the CNS? (Parasympathetic & Sympathetic)
Parasympathetic = Brain Stem and Sacral Region of SC
Sympathetic = Thoracic and Lumbar Region of SC
What are the different Locations of Autonomic Ganglia? (Parasympathetic & Sympathetic)
Parasympathetic = Near effector tissue
Sympathetic = 2 ganglion chains along either side of the vertebral column
What is the difference in Neurotransmitters & Receptors in
Parasympathetic & Sympathetic
Parasympathetic = Postganglionic are CHOLINERGIC - Releases Ach - binds to cholinergic receptors
Sympathetic = Postganglionic are ADRENERGIC - Releases Norepinephrine - binds to adrenergic receptors
What is the exception of the 2-Neuron Chain?
There is DIRECT INNERVATION of Adrenal Medulla by SNS to stimulate EPINEPHRINE secretion into blood --> BINDS TO ADRENERGIC BETA 2 RECEPTOR
Catecholamines
Acetyl group with one chemical change... some type of group added to it
Adrenal Cortex surrounds....
Adrenal Medulla
Adrenal Cortex
True endocrine gland
Adrenal Medulla
Modified sympathetic ganglion
Sympathetic Nervous System has what kind of situations?
'E Situations' - Emergency, Emotional, Exercise
How does the SNS effect the airways?
smooth muscle RELAXES - action: through epinephrine BEING RELEASED and binding to Beta2 receptors
How does the PNS effect the airways?
smooth muscle CONSTRICTS
What is special about the Adrenal Medulla?
only ONE neuron chain - results in epinephrine being released as hormone into blood - epinephrine acts like NorEPI, just last longer - PROLONGS RESPONSE
What happens when Norepinephrine is released onto a blood vessel and binds to an ALPHA receptor?
VASOCONSTRICTION ---> INCREASE BP
What happens when Norepinephrine is released onto a blood vessel and binds to an BETA receptor?
(also happens on skeletal muscle)
VASODILATION --> INCREASE BLOOD FLOW TO ORGANS
Neuroeffector Junction
The synapse between a POSTganglionic autonomic neuron and its target cells
VARIOSITES
series of swollen areas at their distal ends of neurons containing Neurotransmitters - Like a beaded chain - more widespread than a neuron signaling another neuron
Control of target by modulating the concentration of neurotransmitter in the synapse
Diffuses away, Metabolized by enzymes in the ECF, and Reuptake and degradation by Monoamine Oxidase
What happens in Somatic Motor Neurons? [OVERVIEW]
Excitatory of skeletal muscles, mostly voluntary, Single myelinated neuron from CNS to skeletal muscles, and Acetylcholine is released and binds to Nicotinic Receptors
Neuromuscular Junction
Consists of axon terminals and MOTOR END PLATE on the muscle
Membrane is HIGHLY FOLDED
What kind of receptor is found on parasympathetic target cells?
Cholinergic Receptor
Synaptic Cleft at Neuromuscular Junction
The Cholinergic Nicotinic Ach Receptor binds 2 Ach Molecules, opening cation channel for Net Na+ INFLUX --> depolarized the muscle fiber
Skeletal Muscle
muscle cylinders = muscle fibers = muscle cells that fuse together and form cylinder shape
*
STRIATED
*
Cardiac Muscle
muscle cylinders = muscle fibers = muscle cells that fuse together and form cylinder shape, BUT IS HIGHLY BRANCHED
*
STRIATED - centrally located nuclei
*
Intercalated Disk
Where GAP JUNCTIONS are located IN BETWEEN EACH MUSCLE
Smooth Muscle
NOT STRIATED
-Most part = single cells that function together as one unit
Muscle Cells that are fused together are called....
Muscle Fibers
Hypertrophy
Muscles grow by size
Fascicles
Bundled fibers surrounded by connective tissue
Epimysium
Connective tissue surrounding ALL fascicles in muscle - WRAPPING UP ALL THE FASICLES
Endomysium
Connective tissue around muscle fibers
Structure of Muscle Fibers
Sarcolemma, Sarcoplasm, Sarcoplasmic Reticulum, T-Tubules, and Myofibrils`
Sarcolemma
Cell Membrane
Sarcoplasm
Cytoplasm (with # of mitochondria, Glycogen, and Myoglobin)
Sarcoplasmic Reticulum
Endoplasmic reticulum, Stores Ca2+
Transverse Tubules (T-Tubule)
Connected with Sarcolemma
Myofibrils
Contractile structures made of thick and thin filaments
What is a thin filament of a myofibril made of?
Myosin
What is a thick filament of a myofibril made of?
Actin
What is myosin
A motor protein that has intertwined tails, a moveable hinge region, and the head region
What does the Myosin Head Region do?
#NAME?
What proteins are associated with thin filament?
Troponin and Tropomyosin
Cross - Bridge
Myosin Head binds Actin
Troponin is made of....
3 Protein Subunits
Tropomyosin
Covers sites at rest
Why is Tropomyosin elevated during a heart attack?
The muscle is literally torn and broken open, thus tropomyosin is then released into blood
Dystrophin
helps anchor to sarcolemma
Titin
The largest protein in the body
What happens when someone has Muscular Dystrophy?
PROBLEMS WITH DYSTROPHIN, which helps anchor to carcolemma
What happens to the sarcomere during contraction?
It shortens
Neuromuscular Junction Signaling
Motor Neuron releases Ach -> Bind to nicotinic AchR ->AP generated
Excitation-Contraction Coupling
AP conducted across Sarcolemma -> Opens Voltage- Gated Ca2+ channels on Sarcoplasmic Reticulum -> intracellular Ca2+ levels increased
Sliding Filament Theory
Ca2+ binds TROPONIN -> Actin - Myosin CROSSBRIDGE formation -> Power Stroke of Myosin Heads
SLIDING FILAMENT THEORY STEPS
When CALCIUM levels are elevated in sarcoplasm:
-Calcium binds Troponin C -->
-Tropomyosin moves away from actin to expose myosin-binding sites on actin -->
-Myosin HEADS binds tightly to actin - (FORMS A CROSSBRDIGE)
-POWER STROKE = movement of myosin he
The Contraction Cycle - occurs before calcium binds
-ATP binds to Myosin and is HYDROLYZED
-ADP and P remain bound to myosin head
-Myosin head is in position
-Upon binding of Actin with high affinity, Phosphate is released & Power Stroke occurs
*
POWER STROKE
* = movement of myosin heads
Rigor State
High affinity & high force binding between Actin and Myosin UNTIL NEW ATP PRESENT
What happens to Ach that was released?
Broken down by Achesterase or diffused away
Where does the cell get ATP from?
MITOCHONDRIA and AEROBIC RESPIRATION
Metabolic Pathways to Obtain Energy (3)
Creatine phosphate, Anaerobic Glycolysis, and Aerobic Respiration
Creatine phosphate
Short acting; donates Phosphate group to ADP to replenish ATP
Hypertrophy
INCREASE muscle size (high thick/thin filaments)
Where does Creatine go?
Excreted through urine as a waste product
Anaerobic Glycolysis
Glucose --> Pyruvate
-Rapid, No O2 needed; lactic acid can be generated; small amount of ATP synthesized
Aerobic Respiration
In mitochondria; slower, REQUIRES O2, large amount of ATP Synthesized
How is the heart positioned?
In Mediastinum of Thoracic Cavity
How is the Apex of the heart positioned?
Toward 5th intercostal space of ribs
What is the heart encased in?
Pericardium membrane
Pericardium
Double-layer serous membrane filled with ~25ml fluid in cavity to reduce friction - lubrication - reduce inflammation, pain, and friction
What are the layers of the Pericardium?
#NAME?
3 Layers of the Heart Wall
Epicardium, Myocardium, and Endocardium
Epicardium
Outermost Layer/ Superficial Layer
*
SAME THING AS VISCERAL LAYER
*
Myocardium
Most of heart wall - cardiac muscle
Endocardium
Inner lining of thin layer of simple exchange epithelium
Describe Contractile Cells
Branched, have a single nucleus, and are joined by junctions known as INTERCALATED DISCKS with GAP JUNCTIONS
Myocardium has what kind of arrangement?
Spiral
Where does the Aorta pump blood to?
Blood to the BODY
Where does the Pulmonary trunk pump blood to?
Blood to the LUNGS
What are special muscle projections in the heart?
Papillary muscles
What do Papillary Muscles do? What do they look like?
Cone shaped muscles that are attached to chordae tendineae that are then connected to valves
Right AV Valve is what kind of valve?
TRICUPSID VALVE
Left AV Valve is what kind of valve?
BICUPSID VALVE ; Mitral Valve
Why do the valves of the heart open?
Due to differences in pressures between chambers
What happens when pressure to valves is greater than ventricles?
AV Valves open and blood flows into ventricles
How are the AV Valves attached?
to CORD - LIKE TENDONS that connect to bands of PAPILLARY MUSCLES
Where are the Semilunar Valves?
At the base of the large arteries from heart
What side is the Aortic Semilunar Valve on?
LEFT
What side is the Pulmonic Semilunar Valve on?
RIGHT
When do semilunar valves open?
When there is a pressure differences between ventricles and blood vessels
When do semilunar valves open?
When pressure on ventricle greater than in blood vessel
When do semilunar valves close?
When blood ejected into blood vessel
What do right and Left coronary arteries do?
Supply oxygenated blood to heart
What is Distal to the Aortic Semilunar valve?
An opening to CORONARY ARTERIES
What is the Interventricular Septum is made up of?
Fibrous connective tissue skeleton
OVERVIEW OF SEMILUNAR VALVE??
The Semilunar Valve prevents blood that has been ejected into the arteries from flowing back into the ventricles during ventricular relaxation
Valve Disorders (2)
Stenosis and Regurgitation
Stenosis
Opening is too Narrow
Regurgitation
Valves don't close completely - flow backwards
2 Types of Cells Contribute to Heart Pumping
Contractile Cells (Cardiomyocytes) AND Autorhythmic Cells (Nodal Cells)
Contractile Cells (Cardiomyocytes)
Organized into sarcomeres ; T-Tubules, and Sarcoplasmic reticulum (stores calcium)
Autorhythmic Cells (Nodal Cells)
Smaller, without organized sarcomeres & Spontaneous generation of AP's
General Mechanisms of Cardiac Myocyte Contraction
#NAME?
What makes sodium start to enter a skeletal muscle?
#NAME?
EXCITATION CONTRACTION COUPLING [OVERVIEW]
#NAME?
CARDIAC MUSCLE [OVERVIEW]
-STIMULATED BY ELECTRICAL CELLS THAT MAKE ACTION POTENTIALS
STILL NEED DETAILS
-CAUSES MUSCLE CELLS TO HAVE ACTION POTENTIAL
-STARTS AT REST AND WHEN AP GETS TO HEART MUSCLE CELLS, IT WILL OPEN WHEN THE AP GETS THERE --> OPENS SODIUM CHANNEL = DEPOLARIZAT
Action Potential Curve for Cardiac Muscles (Phases)
0. Na 'fast' channels open = DEPOLARIZATION
1. K+ channel transiently open; Na+ channels close
2. Ca2+ Channels OPEN; PLATEU
3. Slow K+ Channels Open; Ca2+ channels close = REPOLARIZATION
4. Resting Membrane Potential
Excitation - Contraction Coupling in Cardiac Muscle
STEPS:
1. AP is signaled in Cardiac Muscle (initiated by Nodal Cells - spontaneously generated)
2. Opens L-Type Ca2+ Channels on T-Tubules --> Ca2+ Enters from ECF** - now the trigger
1. L-Type for LONG
3. Ca2+ opens Ryanodine Receptor on SR (sarcoplasmic reticu
How does Excitation - Contraction Coupling SHUT OFF:
7. Ca2+ unbound from Troponin
8. Ca2+ - ATPase pumps Ca2+ back into SR
A. CANT PUMP CALCIUM OUT WITHOUT ATP
9. ALSO, Ca2+ out of cell thru Na+ / Ca2+ Exchanger
A. ESTABLISHES LOCAL GRADIENT
10. Na+ - K+ ATPase drives counter-transport
SNS Effects Contractility - more force = more blood ejected: NEpi binding to Beta 1 receptor (adrenergic receptor) WHICH LEADS TO?
INCREASE CONTRACTILE FORCE (Inotropy)
--> Increased Ca2+ Influx via VOLTAGE - GATED Ca2+ Channel
(L Type Channel on Membrane)
Excitation of heart initiated by Sinoatrial (SA) Nodal Cells (In right atrium wall) involves what?
#NAME?
How do Nodal cells differ from Contractile cells?
-RMP less negative (-60mV) = *
CLOSER TO THRESHOLD --> DEPOLARIZATION
*
-Cells constantly permeable to Na+ at "rest" thru Na+ Leak Channels (Pacemaker potential)
What do Nodal Cells do AT THRESHOLD?
#NAME?
Pathway of Excitation through the Heart [not explaining]
1. SA Node
2. Internodal Pathway
3.Atrioventricular Node
4.AV Bundle
5. Right & Left Bundle Branch
6. Purkinje Fibers
Pathway of Excitation through the Heart [explaining]
� Signal initiated in the SA Node
� AP travels through internodal tracts to the AV Node
? Signal delayed ~0.1 seconds in AV Node
� And Signals Atrial Muscle --> followed by Atrial Contraction
� AP travels through AV Bundles & down IV Septum through the R/
What happens when the Atrial Muscle Contracts?
Remaining blood flows to the Ventricles
What happens when the ventricles contract?
Blood exits through large arteries
WHAT NERVE ACTS ON PARASYMPATHETIC NERVE SLOWS DOWN Heart Rate?
VAGUS NERVE - CARNIAL NERVE 10
Where is Epinephrine (ADRENALINE) PRODUCED?
Adrenal Medulla
Rest-and-Digest
Parasympathetic Division
Fight-or-Flight
Sympathetic Division
What does the Phrenic Nerve innervate?
Thoracic - Diaphragm