Shared Flashcard Set

Details

Physiology-Circulation
Exam 3
29
Physiology
Undergraduate 3
12/01/2013

Additional Physiology Flashcards

 


 

Cards

Term
Components of a circulatory system
Definition
1. circulating fluid
2. vascular system (network of tubes/vessels)
3. pump
Term
Primary functions of a circulatory system
Definition
1. Transportation
allows for large, specialized surface areas to transport products; ex: intestines, lungs
three kinds of transportation: respiratory, nutritive, excretory

2. regulation
two kinds of regulation: hormonal (global impact), temperature (heat travels to maintain temperature)

3. protection
two kinds of protection: clotting, immune system (circulation of white blood cells)
Term
open circulatory system
Definition
system in which there is no distinction between circulatory fluid and extracellular fluid of body tissues

in anthropods, molluscs (huge diversity in design)
has low pressure
less efficient (wastes respiratory pigments)
no control over distribution
components: heart, arteries/vasculature, hemolymph, sinuses/ostia (where fluid enters vasculature)
Term
closed circulatory system
Definition
system in which circulatory fluid (blood) is always enclosed within vessels that transport fluid to and away from the pump

in all vertebrates and some invertebrates
components: heart, arteries, capillaries, veins
Term
arteries
Definition
vessels moving away from heart
Term
capillaries
Definition
site of exchange (from arteries to veins)
Term
veins
Definition
vessels leading to heart
Term
heart and circulation of a fish
Definition
linear set up of heart
sinus venosus: collection chamber
atrium: collection chamber
ventricle: pumping chamber
conus arteriosus: pumping chamber
Term
heart and circulation of terrestrial vertebrates
Definition
has subdivision of circulation
pulmonary: to the lungs (respiratory)
systemic: to the rest of the body
Term
heart and circulation of amphibians
Definition
amphibians are pulmocutaneous: have gas exchange in respiratory system and in skin

components:
sinus venosus: bring blood from body into R atrium
**sub-divided atrium: 2 atria
systemic arch: out to body
L/R pulmocutaneous arteries: structures that separate blood flow
**conus arteriosus: helps to subdivide blood flow
ventricle: main pump, has folds in the walls that help direct blood flow
Term
heart and circulation of reptiles
Definition
components:
**septum: blockage that routes oxygenated/deoxygenated blood to the correct artery
ventricle: main pump, folds in wall that direct blood flow
R/L aorta
R/L common pulmonary arteries
R/L pulmonary arteries
Term
heart and circulation of mammals and birds
Definition
components:
sinus
2 atria
2 ventricles
pulmonary artery
aorta
veins
Term
Heart anatomy
Definition
R atrium: receives blood from body
L atrium: receives blood from lungs
R ventricle: sends blood out to body
L ventricle: sends blood out to lungs
Tricuspid valve (R side) and Bicuspid valve (L side): valves between atrium and ventricle that prevent backflow of blood into atrium
Term
Heart contraction
Definition
muscle cells contract when depolarized
cells are electrically coupled (neighboring cells depolarize together)
waves of depolarization cause coordinated contraction of heart

Sequence of events:
1. mid-diastole: blood flows into atrium
2. atrial contraction: blood flows from atrium into ventricles
3. isometric ventricular contraction: pressure in ventricles because of blood flow in
4. ventricular ejection: valves pop open
5. isometric ventricular relaxation: valves close
Term
Pacemaker cells
Definition
cells located in the sinoatrial node that determine heart rate; can change heart rate by decreasing/increasing time between heart beats

neurogenic pacemakers: signal from CNS, still have neural input; causes heartbeat NOT heart rate
myogenic pacemakers: group of electrically-coupled muscle fibers that stimulate contraction, causes heartbeat based on activity of heart alone, **FASTEST one drives the system**


*Adenosine and Acetylcholine reduce starting voltage of pacemaker potential, which slows pacemaker potential and heart rate
*Norepinephrine accelerates pacemaker potential and heart rate
Term
vertebrate heart muscle fibers
Definition
1. small muscle fibers: weak, don't contract well, autorhythmic (have own, rhythmic depolarization)
located in top of atrium

2. medium muscle fibers: bulk of heart fibers, contractile
located in walls of heart

3. large muscle fibers: don't contract, have rapid electrical conduction
located in bottom of atrium

small, medium, and large fibers work together to cause waves of contraction by pushing blood out through the ventricle
Term
1 heartbeat cycle
Definition
cycle: rhythmic contraction (systole) and relaxation (diastole) of whole cardiac muscle mass system
Term
cardiac pacemaker potential
Definition
steady depolarization after an action potential
pacemaker potentials don't have a resting potential
every time you go over the threshold, you get a heart beat

there is an offset in time between atrial contraction and ventricular contraction
atrial depolarization, ventricular depolarization, then ventricular repolarization
Term
Frank-Starling mechanism
Definition
contractile properties of heart muscles adapt to changing conditions

if a heart fills with greater volume of blood, it will contract with greater force

filling pressure: volume of fluid into heart; increased volume causes increased filling pressure
stroke volume: blood ejection from heart ventricles; increased contraction causes increased stroke volume

stroke volume/filling pressure: when heart has pumped out all the blood it can, system is killed; the positive relationship has a limit
Term
factors affecting end-diastolic volume
Definition
end-diastolic volume: volume of blood in ventricle at end of filling phase

-distensibility of ventricle (ability of fivers to stretch)
-thickness of walls of ventricle: if they are too thick, the walls cannot stretch to fill
-strength of arterial contraction
-venus filling pressure (amount of blood from venus system)
-filling time (increased time causes increased fluid)
Term
factors affecting end-systolic volume
Definition
end-systolic volume: volume of blood in ventricle at end of contraction

-force of ventricular contraction
-how much arterial backpressure there is
Term
blood flow
Definition
determined by pressure and resistance

pressure: force/area; pumping of heart is source of pressure in system (increased pressure causes increased flow)

resistance: how much we are fighting flow in system due to friction with the walls of vessels and within fluid layers; impacted by viscosity (blood is 3-4x more viscous than water, plasma is less viscous than blood)

boundary layer: thickness of walls of vessel; as diameter of vessel changes so does resistance
turbulent blood flow: unsteady flow can be caused by physical obstructions of viscocity

Q=(P1-P2)/R

highest resistance in circulatory system: capillaries (smaller vessels so more obstructions)
highest pressure in circulatory system: arteries
Term
4 primary functions of arterial system
Definition
1. act as a conduit (delivery system)

2. damp oscillations in pressure and flow; smooth out flow

3. act as a pressure reservoir for forcing blood back into the small-diameter arterioles

4. control distribution of blood via structure constriction of terminal branches of arterial tree
Term
pressure oscillations
Definition
pressure oscillations: expanding and contracting (elasticity) of arteries
arteries closer to heart have more elasticity than arteries further from the heart
larger pressure oscillations in arterial system, want smaller oscillations in capillaries and veins
less resistance means a smoother blood flow
ventricle is source of oscillations
aorta needs elasticity to reduce turbulence flow, because without elasticity it wouldn't recapture energy and blood would just be sucked back in
Term
venous system
Definition
primary function is to return blood to heart
also largely functions as a reservoir/storage (stores 50% of blood volume)

vein is more floppy
-allows for continuity of flow, valves in vein are there so gravity doesn't pull down blood, muscles aid by squeezing
-countercurrent warms veins from arteries (endothermic)
-fat cells around blood vessels prevent loss of heat

increased venous return causes increased stroke volume which causes increased cardiac output
Term
thoracic expansion
Definition
expansion that helps fluid return by pulling blood from head and neck
Term
capillary system
Definition
primary function is to bring circulating fluid and nutrients through system into contact with tissues; extensive network

form and function:
-different cells have different kinds of transfers
-necessary for metabolism, plasma/fluid transfer, uptake into circulation

pressure and flow:
1. physical pressure: blood pressure pushes fluid out
2. colloid osmotic pressure: many mores pull fluid in (arterial-away, venous-in)


continuous capillaries: narrow and thing, many vesicles, small cleft, diffuse, move through endothermic cells, most common and least permeable
ex: muscles, neuronal, lungs, connective tissue, exocrine, glands

fenestrated capillaries: no longer have narrow clefts so pores are relatively permeable, less vesicles
ex: intestines, endocrine glands, renal glomerulus

sinusoidal capillaries: has big holes, most permeable, no vesicles, rare
ex: liver, bone marrow, spleen, lymph nodes, adrenal cortex
Term
factors that affect blood flow in capillaries
Definition
-arteries changing diameter and flow rate

-precapillary sphincter (muscle cell contracts/dilates)
hyperemia: increased blood flow to tissue
ischemia: decreased blood flow to tissue
systemic: neutral blood flow
local control: myogenic response leads to excess fluid, causes increased stretching and contracting of artery to maintain its diameter

-chemical triggers: local chemicals either cause vasodilation or vasoconstriction
vasodilation: dilation of vessels increases blood flow
vasoconstriction: constriction of vessels, decreases blood flow
CO2: increases oxygen uptake
NO: inflammatory chemical, produced/released by vascular endothelium (causes smooth muscle to relax)
endothelin: vasoconstrictors released in response to stretch of vessels
prostacyclin: released by vascular endothelium, causes vasodilation and decreased clotting
Term
factors that affect blood pressure
Definition
-heart rate
-stroke volume
-resistance
Supporting users have an ad free experience!