bio unit 4 Flashcards
(75 cards)
what do we require from the enviroment
nutrients and oxygen
how is the rate of diffusion o oxygen and nutrients limied and what is the solution
it is limited by distance
- cardiovascular system for transoport of substances through the body
- transported by flow of blood through circulatory system
- bulk flow rather than diffusion
what are the materials transported from the external environment to tissues
nutreints, water, gases (especially o2)
between tissues of body
wastes, nutrients, hormones
from tissues to external environment
metabolic wasted, gases (especially CO2), heat
what is the cardiovascular system with components
series of tubes (blood vessels) filled with fluid (blood) and connected to a pump (heart)
what is he pericardium
it is part of the external anatomy of the heart, a tough membranous sac surroiing the heart, made up of epicardiu and parietal layer of pericardium with a small amount of fluid between them that acts as a lubricant
what are coranary atary
part of the external anatoy of the heart
- nourisht he heart muscle with blood
what does the heart demand for
oxygen and this depends on adequete blood flow , if lacks then leads to hear attack (myocardial infraction)
what is the left atrium
part of the internal anotome, recieves oxyginated blood from the pulmonary veis and sends to left ventricle
what is the left ventricle
receives oxygenared blood from left atrium and sends to body, after going through body retuns back to the heart via superior vena cava (this cycle is called the systemic circuit)
right atrium
recieves deoxygiinated blodd from venae cavea and sends to right ventricle
right ventricle
recieves deoxygentated blood from the right atrieum and sends to lungs ( via pulmonary trunk)
what are valves and what are the two types of valves
ensure flow is unidirectional
Atriovetnriular valves (tricuspid and bicuspid)
semilunar valves (Aortic and pulmonary)
what is atrioventricular valves and what holds them
tricuspid and bicuspid
atached on ventrucular side to collagenous cord(chordinae tendineae (prevent valves from bieng pushed back into the atrium)
what is semulunar valves and what holds them
Aortic and pulmonary
- prevent backflow into ventricles
- the semilunar valves do not need cords to brace them because of thier shape
what are the two divisions of the path of blood flow and describe them
pulmonary circuit, blood vessels in the lungs and those that connect the lunds to the heart
systemic circuit, encompases the rest of the blood vessels in the body
describe the path of the two cardiovascular system divisions
page 92
what does the heart do to blood pressuse
increases it
what are the specialized cells of the heart
they are autorythmic cells (oacemaker cells) need then bc heart don’t get activated by the nervous system
located in sinoatrial node (SA node)
right atrium, near superioir vena cave,
and spontaneously generate action potentials withought input fom the nervous system
what is the membrane potential for pacemaker cells
have an unstable membrane potential that slowly drifts upwards from starting point og -60 mV until reaches threshold and iniates action potential
no resting membrane have special If channels
permeable to K+ and Na+
when membrane potential is negative:
Na+ influx > K+ efflux, net influx of + charge, slow depolarication of membrane
when membrane potential is positive
If channels close, Ca2+ channels open, contiend depolirzation, threshold reached, many Ca2+ channels open and rapid influx of Ca2+, steep depolarization phase of action potential
what happens during repolarization
at the end of depolarizaio the Ca2_ channels close and K+ channels open slowly;efflux of K+ causes repolarization