ch 01, 6 levels of organization, metabolism, homeostasis, feedback.txt

Anatomy

science of body structures and relationships

Physiology

science of body functions

6 levels of organization (smallest to biggest)

chemical, cellular, tissue, organ, system, organismal

chemical level

includes atoms and molecules

Molecules

two or more atoms joined together (ie: DNA, glucose)

Atoms

smallest unit of matter (ie: carbon, oxygen)

cellular level

molecules combine to form cells (ie: muscle, nerve, epithelial, RBC)

cells

basic structural and functional unit of an organism

tissue level

group of cells and materials surrounding them

4 types of tissue

epithelial, connective, muscular, nervous

Where are all four tissues found

small intestines

organ level

tissues are joined to form organs

Organ

structures composed of 2 or more different types of tissue

Types of organs in urinary system

kidney, ureters, urinary bladder, urethra

system level

consists of related organs with common function (ie: digestive system: breaks down and absorbs food, includes organs such as mouth, stomach, etc.)

Metabolism

sum of all chemical processes in the body

catabolism

breakdown of complex chemical substances into simpler components

anabolism

building up of complex chemical substances from more simpler components

Homeostasis

condition of equilibrium (balance) in the body's internal environment

Intracellular fluid (ICF)

fluid within cells (ie: cytoplasm)

Extracellular Fluid (ECF)

fluid outside cells

Types of ECF

blood plasma (within blood vessels), lymph (within lymphatic vessels), synovial (in joints), aqueous humor and vitreous body (in eyes)

cerebrospinal fluid

type of extracellular fluid that holds the brain and spinal chord

Feedback system components and role

receptor - monitors change in controlled condition, sends input to the control center (ie: nerve ending of the skin in response to temp change), control center - evaluates input from receptors and generates output command (ie: nerve impulses, hormones - brain acts as control center receiving nerve impulses from skin temp receptors), effector - receives output from the control center, produces a response that changes the controlled condition (shivering to generate heat)

Negative Feedback system

reverses a change in a controlled condition (ie: regulation of blood pressure)

Positive Feedback system

strengthens or reinforces a change in one of the body's controlled conditions (ie: childbirth)

positive feedback example - blood loss

when blood loss, blood pressure drops, cells receive less oxygen and function less, and if blood loss continues, heart becomes weaker and stops to pump at all

negative feedback example - regulation of blood pressure

baroreceptors detect high BP, send nerve impulses (afferent or sensory) to brain to interpret, brain sends back nerve impulses (efferent) to heart and blood vessels, which drops BP and restores homeostasis.