Unit 1 - Intro to Physiology Flashcards
Physiology = ?
Study of the normal functioning of a living organism and its component parts
1) structure & function relationships
2) biological energy
3) info flow
4) homeostasis
Levels of Organization (6)
chemical
cellular
tissue
organ
organ system
organism
tissue types
epithelial
connective
muscle
neural
epithelial tissue functions
- protect internal env
- regulate material exchange
- one or more connected cell layers and basal lamina (basement membrane)
epithelial types
exchange
ciliated
secretory
transporting
protecting
epithelial (exchange)
rapid exchange of gaseous material
epithelial (ciliated)
line airways & female reproductive tract
epithelial (secretory)
synthesize & release products into external env/blood
epithelial (transporting)
selective transport of non-gaseous material
epithelial (protective)
found on body surface
connective tissue functions
provide structure & support; extensive ECM (containing proteoglycans, collagen, elastin, fibronectin)
connective tissue types (5)
loose
dense
adipose
blood
supporting
connective - loose
elastic tissue
connective - dense
strength (primary function)
connective - adipose
white and brown fat
connective - blood
watery matrix lacking insoluble protein fibers
connective - supporting
dense substances (e.g. cartilage, bone)
muscle tissue function
ability to contract -> produce force & movement
muscle tissue types (3)
skeletal
smooth
cardiac
muscle - skeletal
gross body movement
muscle - smooth
influence movement of substances in/out/within body
muscle - cardiac
only in heart; contraction moves blood through body
neural tissue function
carry info from one part of body to another; v little ECM
neural tissue types (2) & their functions
neurons - carry info as electrical or chemical signals
glial cells - supporting cells for neurons
which of the following allows the movement of gases across epithelium?
a) ciliated
b) protective
c) secretory
d) exchange
e) transport
d) exchange
organ systems (10)
nervous
musculoskeletal
circulatory
respiratory
immune
endocrine
reproductive
digestive
urinary
integumentary
difference between “function” & “mechanism”?
function - why system exist?
mechanism - how system work?
- mechanism is studied to understand function
characteristics of homeostasis
- maintenance of relatively stable internal environment
- auto control mechanisms
result of homeostasis?
oscillation around set-point
can setpoints change w time?
yes; acclimatization - environmentally induced change in physiological function w no genetic change
cell-to-cell communication mechanisms (4)
gap junction
contact-dependent signals
local communications
long-distance communication
gap junction
direct cell-to-cell comms
- occurs via connexons (protein channels) between adjacent cells
- can open/close
- in many cell types
contact-dependent signals
- interaction between membrane molecules on two cells
- immune cells & during development
local communications
communication w neighbouring cells
- via paracrine(act on neighbour)/autocrine (act on self) signals
long-distance communication
- responsibility of nervous & endocrine systems
- nervous system: combination of chemical/electrical signals (e.g. neurohormones, neurotransmitters)
- endocrine system: chemical signals (hormones)
why do some cells respond to a chemical signal and others do not?
target cells have various receptor proteins; only respond if appropriate receptor
receptors
usually trans-membrane proteins (or glycoproteins)
usually found in plasma membrane, but can be cytosolic/nuclear
membrane spanning receptor (3 main regions) - think “Y”
A. extracellular domain (binding ligand)
B. trans-membrane domain (hydrophobic)
C. intracellular (cytoplasmic) domain (activating cellular response
Receptors vs Chemical signals
- receptor, not just the signal, determine type of response
- any molecule binding w receptor -> response (agonist - response; antagonist - no response)
responses to chemical signals (4 steps)
- signaling molecule binds to receptor
- activated receptor interacts w molecules inside cell to start signal
- signal carried to appropriate place in cell -> signal transduction
- response occurs
homeostasis can be maintained by local/long-distance pathways. define local control & reflex control.
local control - effects exerted on neighbouring cells
reflex control - reaction in one or more organs controlled from elsewhere in body; can be any long-distance path from nervous and/or endocrine
Key points about homeostatic control systems (6)
- stability = result of balance between input & output
- negative feedback returns variable to original condition
- maintain similarity, not constancy
- setpoints can be reset
- some variables controlled more closely than others
- most control systems require communication between cells
Response loop steps (7, general)
stimulus
sensor/receptor
afferent/input pathway
integrating center
efferent/output pathway
target/effector
response
Types of feed/control loops (3)
negative feedback
positive feedback
feedforward control
negative feedback
- results in a change that removes signal, returning variable to original value
- allows for homeostasis (oscillation; keeps system near set-point)
positive feedback
- response sends a signal -> reinforce stimulus, sending variable further from set-point until external signal turns response off (e.g. labour)
- NOT homeostatic
- sends system temporarily out of control
feedforward control
- anticipatory control: predicts incoming change
->starts response loop to prevent change
e.g. smelling food
where can receptor molecules for chemical signals be found?
a) membrane
b) cytosol
c) nucleus
d) a and c
e) all
e) all
