cardiovascular system notes

Who proved that circulatory system is unidirectional and closed

william harvey

harvey’s circulation experiment

tied a tourniquet around someone’s arm and applied pressure to veins

4 chambers of the heart

2 atria and 2 ventricles

difference between atria and ventricles

atria collects blood, ventricles pump blood

systemic and pulmonary circulation

systemic = all around the body, pulmonary = to and from the lungs

left vs. right side

left supplies oxygenated blood to systemic circulation, right supplies deoxygenated blood to pulmonary circulation

arteries

carry blood away from heart ventricles to tissues and lungs at high pressure

narrow lumen (tunica intima)

inner layer of artery, maintains blood pressure at 80-120 mmHg

Tunica media

layer of muscle and elastic fibres that contract and stretch with pulse

Tunica externa (adventita)

thick layer of collagen that prevents artery from rupturing

muscle fibres vs. elastic fibres

muscle fibres maintain rigidity and contract to increase pressure, elastic fibres stretch with blood flow

lumen

the hollow passage in an artery through which blood flows

elastic recoil

pressure exerted on artery is returned to blood when artery size goes back to normal

systolic blood pressure

higher blood pressure when the heart contracts

diastolic blood pressure

lower blood pressure when heart relaxes

vasocontriction

muscles around arteries constrict to resist blood pressure

vasodilation

muscles around arteries relax

flow of blood

heart—>arteries—>arterioles—>capillaries—>venules—>veins—>heart

types of capillary walls

continuous, fenestrated, sinusoid

continuous capillary walls

held together by tight junctions

continuous capillary walls

held together by tight junctions

fenestrated capillary walls

have pores in tissues specialized for absorption such as kidneys and intestines

sinusoidal capillary walls

open spaces between cells, permeable to large molecules (for example in the liver)

higher/lower hydrostatic pressure

higher pressure at arterioles—>from blood to tissue, lower pressure at venules—>from tissue to blood(waste, CO2)

veins

collect blood from tissues and convey it to heart’s atria at low pressure

veins contain ___ to prevent backflow

one way valves

skeletal muscle contraction

skeletal muscles surrounding veins contract to encourage blood flow in low pressure veins

veins run parallel to arteries

pulse from arteries stimulates blood flow in veins

vessel comparison graph

contraction of the heart is

myogenic = contraction comes from heart tissues

_____ directs contraction of heart tissue

SA Node (sinoatrial node)

primary pacemaker

SA Node —> secondary pacemaker (AV Node) —> Tertiary Pacemaker (Bundle of His)

fibrillation

irregular and uncoordinated heart contraction

electrical conduction

causes delay in heart contractions, allows for blood to fill up into ventricles following atrial contractions

parts of the heart

labeled

which part of the brain involuntarily controls the heart contractions

medula oblangata

which nerve connected to medula oblangata increases heart rate

sympathetic nerve

which nerve connected to medula oblangata decreases heart rate

parasympathetic nerve (vagus nerve)`

where is the adrenal gland found

on kidneys