A & P Unit III Ch 8 The Brain

Brain - Major Parts

Brain Stem

1) medulla oblongata, 2) pons, 3) midbrain, 4) substantia nigra, 5) reticular formation

The brainstem controls several important functions of the body including:
Alertness, Arousal, Breathing, Blood Pressure, Digestion, Heart Rate Other Autonomic Functions
Relays Information Between the Peripheral Nerves and Spinal Cord to the Upper Parts of

Brain Stem

Contains 2 vital nuclei; Cardiovascular center; Regulates heart rate, blood pressure
Medullary rhythmicity area ; Adjusts respiratory rhythm

Medulla Oblangata
Brain Stem

Serves as a "bridge"; Connects medulla to midbrain and above; Contains ascending and descending tracts; Connects left and right sides of cerebellum

Brain Stem

Functions of the mesencephalon include:Controlling Responses to Sight, Eye Movement, Pupil Dilation, Body Movement, Hearing

Brain Stem

An area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons

substantia nigra
Brain Stem

A nerve network in the brainstem that plays an important role in controlling arousal.

reticular formation
Brain Stem

Diencephalon: thalamus, hypothalamus, pituitary gland, epithalamus, pineal gland


motor, autonomic, and consciousness functions



hypothalamus, A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

pituitary gland

Master gland, A gland that controls growth


Contains pineal body. Involved in olfactory senses and sleep/wake cycle

pineal gland


Cerebellum: peduncles, cerebral hemispheres, cerebellar cortex, white matter

The "little brain" part of the hind brain. Connected to brain stem by 3 cerebellar peduncles. Consists of 2 laterally, large hemispheres which are united by a midline "vermis"


Massive fiber bundles; one group links the brainstem with the cerebellum (cerebellar peduncles) and another is present on the ventral aspect of the midbrain containing descending fibers from the cerebral cortex to the brainstem and spinal cord (cerebral p

cerebral hemispheres

Divided into right and left by the cerebrum.

cerebellar cortex

the cortex that covers the surface of the cerebellum

white matter

The portions of the central nervous system that are abundant in axons rather than cell bodies of neurons. The colour derives from the presence of the axon's myelin sheaths

Area of the brain responsible for all voluntary activities of the body


left controls right side of body; right controls left side of body; in cerebrum

left and right hemispheres


Connects the left & right hemispheres., A thick band of axons that connects the two cerebral hemispheres and acts as a communication link between them.

corpus callosum

the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments

frontal lobes

Portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

parietal lobes

Portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear.

temporal lobes

the portion of the cerebral cortex lying at the back of the head; includes the visual areas, which receive visual information from the opposite visual field

occipital lobes

sulcus that separates the parietal and occipital lobe

parieto-occipito sulcus

Separates frontal lobe from parietal lobe

central sulcus

Primary Motor Cortex

precentral gyrus

postcentral gyrus


area concerned with conscious awareness of sensation; occur in the parietal, insular, temporal, and occipital lobes

sensory areas

primary motor cortex; areas of the three boat cortex for response messages from the brain to the muscles and glands

motor areas

* For autonomic activty in Hypothalamu

integrative centers

Controls muscle activity and posture; largely inhibits unintentional movement when at rest, Clusters of nerve cell bodies located deep within the cerebrum that are important in motor coordination

basal nuclei

frontal sulcus

Separates temporal lobe from parietal and frontal lobes

lateral sulcus

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

association areas

A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus.

limbic system

Cerebral Cortex Lobes, other structures

Cerebral Cortex Lobes

(anatomy) a long narrow slit or groove that divides an organ into lobes


(anatomy) any of the narrow grooves in an organ or tissue especially those that mark the convolutions on the surface of the brain


A ridged or raised portion of a convoluted brain surface.


Fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system.

Cerebrospinal fluid

1. Lateral Ventricles (1st & 2nd)
2. Interventricular foramen
3. 3rd ventricle
4. Cerebral Aquaduct
5. 4th ventricle
6. Apertures to exit 4th ventriclles
has 2 options
- can go upa and around brain (subarachnoid space) to give outer parts buoyancy and cus

CSF Flow

Brain controls opposite side of the body: all sensory and motor pathways cross in CNS
Left side of the brain controls right side of body
Right side of brain controls left side of body
Left hemisphere important for spoken and written language, numerical an

Hemispheric Lateralization

The cervical plexus provides nerve connections to the head, neck, and shoulder.

cervical plexus

The brachial plexus provides connections to the chest, shoulders, upper arms, forearms, and hands.

brachial plexus

The lumbar plexus provides connections to the back, abdomen, groin, thighs, knees, and calves.

lumbar plexus

The sacral plexus provides connections to the pelvis, buttocks, genitals, thighs, calves, and feet.

sacral plexus

3-sensory neuron - a single cell. Carries info from receptors to spinal cord
4-interneuron - passes off info to net sgment of reflex arc and sends info to brain
5-motor neuron

The Reflex Arc

- fast
- automatic
- protected
blink, sneeze, cough
All controlled by same structure - reflex arc

Define reflexes


the process by which axons become coated with myelin, a fatty substance that speeds the transmission of nerve impulses from neuron to neuron

Oligodendrocytes & Shwann Cells

What cell produce myelin?

Nerves that run up and down the length of the back and transmit most messages between the body and brain

spinal cord

31 pairs of nerves coming out from the spinal cord between two vertebrae; dorsal roots are sensory and ventral roots are motor

spinal nerves

Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons.

gray matter

how motor information leaves the spinal cord

ventral (anterior) roots

sensory fibers only *axons from various parts

dorsal (posterior) roots

A swelling located at the entrypoint into the spinal cord of the dorsal root of the spinal nerve, containing the cell bodies of afferent somatic sensory neurons, i.e. neurons concerned with sensing touch, pressure, vibrations, temperature, pain, and myota

dorsal root ganglia

horse's tail", a fan of nerve fibers below the spinal cord

cauda equina

spinal cord gets bigger where nerves branch off the arms and legs in order to accommodate neural processing

spinal enlargements

transmit sensory impulses to the brain

ascending tracts

Carry nerve impulses away from the brain.

descending tracts

the brain chemicals that communicate information throughout our brain and body. They relay signals between nerve cells, called "neurons." The brain uses neurotransmitters to tell your heart to beat, your lungs to breathe, and your stomach to digest. They



two kinds of neurotransmitters

inside of cell is very negative and outside is positive


Resting Membrane Potential - -70 mV, maintained by the Na+/K+ ATPase
1- Pimp polarized - 3 Na+ pumped out & 2 K+ pimped in
Note: Positive outside, negative inside. Na+, in our bodies, is always & very more.concentrated outside of cells; K+ always & very m

Transmission of a nerve impulse

Nodes Of Ranvier

Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node, thus increasing the speed of conduction (saltatory conduction).

A part of the cell containing DNA and RNA and responsible for growth and reproduction


An anatomically distinct collection of sensory or motor neuron cell bodies within the PNS


The all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire. Essentially,


Post synaptic membrane

in a synaptic transmission, this is the membrane that is equipped with receptor sites (proteins) to receive neurotransmitters.

Presynaptic membrane

The part of the cell membrane of an axon terminal that faces the cell membrane of the neuron or muscle fiber with which the axon terminal establishes a synapse.

1- Action Potential reaches the axon terminal and causes Ca+ channels to open, Ca+ rushes in.
2- Calcium causes exocytosis of synaptic vessicles (neurotransmitters will get dumped into cleft)
3- Neurotransmitters diffuse across the cleft and bind receptor

Synaptic transmission


fast, involuntary sequences of actions in response to stimuli
Can be simple, innate
Can be complex, learned
Spinal (reflex arc): simple
Cranial: more complex

Spinal Cord

Blood Brain Barrier




The Limbic System
Is a functional grouping that:
Establishes emotional states
Links conscious functions of cerebral cortex with autonomic functions of brain stem
Facilitates memory storage and retrieval




Oh I - Olfactory nerve (smell)
Oh II - Optic nerve (vision)
Oh III - Oculomotor nerve (eye movements)
To IV - Trochlear nerve/pathic nerve (eye movements)
Touch V - Trigeminal nerve/dentist nerve (sensory and motor) to face)
And VI - Abducens nerve (eye m

Oh, Oh, Oh, to touch and feel a girls veil, such happiness


Lots o stuff