U4, S2: Circulatory System

What are the functions of the circulatory system?

moves blood throughout body, distributes heat, maintains body fluids with help from the kidneys, and is associated with with the immune system

What does the blood carry and transport?

carries nutrients to cells, wastes away from cells, and carries hormones from cells to target tissues

How fast does the heart beat (generally)?

70 times/min

How much blood cycles from the heart and how often?

every 1 minute, about 5L of blood cycles from the heart to the lungs and back to the heart

What is (commonly) another name used for atherosclerosis?

arteriosclerosis

What kind of response creates blood clots?

an immune response

What is the function of the arteries?

carries blood away from the heart

What are the three layers of arteries composed of?

outer layer: connective tissue, middle layer: smooth muscle, inner layer: connective tissue

What happens with each heart contraction?

blood surges from the heart and enters arteries, which creates high pressure resulting in the arteries stretching

What happens when the heart relaxes?

pressure drops and arteries return to original diameter

What are arterioles?

smaller arteries that branch out from "normal sized" arteries

What is the middle layer of arterioles composed of?

elastic fibers and smooth muscle

What controls the diameter of arteries?

sympathetic nerves of the autonomic nervous system

What is vasoconstriction?

contraction of the smooth muscles in arterioles, decreasing blood flow

What is vasodilation?

relaxation of the smooth muscles in arterioles, increasing blood flow

What is the function of precapillary sphincters?

regulate movement of blood from arterioles into capillaries

Where are precapillary sphincters located?

in arterioles

What causes skin to blush/produce a pink colour?

when red blood cells come close to the surface of the skin

When do arterioles open?

only when cells in a specific area require blood

What is atherosclerosis?

degeneration of blood vessels by accumulation of fat deposits

What can atherosclerosis lead to?

high blood pressure, blood clots, and chest pain due to inadequate amounts of blood and oxygen being delivered to the heart

What is an aneurysm?

a birth defect of injury to the inner wall of an artery that is often caused by atherosclerosis

What are the common sites of an aneurysm?

aorta of the heart, abdominal aorta, and arteries in the brain

What are three things that an aneurysm can lead to?

may lead to a stroke, cells may die due to lack of nutrients and oxygen, and artery may bulge

What are capillaries composed of?

a single layer of cells

What are capillaries?

tiny blood vessels that connect arteries and veins, and are the site of fluid and gas exchange

What are two ways capillary beds are destroyed?

high blood pressure or high impact (bruising)

How must red blood cells travel through capillaries?

in a single file

How does oxygen travel from blood to tissues?

oxygen diffuses through capillaries

What are venules?

small veins that connect to "normal sized" veins and transport deoxygentaed blood back to the heart

What are two things that can exchange between capillaries and blood and/or tissue?

water-soluable ions and vitamins through diffusion

What are veins composed of?

smooth muscle, connective tissue, and elastic tissue

How does blood move against gravity?

with help from smooth muscle, skeletal muscle, and valves in veins

What type of muscles surround veins?

skeletal muscle

How does skeletal muscle help control blood flow?

skeletal muscle pushes against vein, causing blood pressure to increase and valves open then close to keep blood moving upwards

What do veins also act as?

blood reservoirs

What causes vericose veins?

increased pooling of blood and prolonged sitting or compression

What kind of blood do arteries transport?

oxygenated blood

What are the only kind of arteries that don't transport oxygenated blood?

pulmonary arteries

What kind of blood do capillaries transport?

both oxygenated and deoxgynated blood

What kind of blood do veins transport?

deoxygenated blood

What are the only kinds of veins that don't transport deoxygenated blood?

pulmonary veins

What causes a pulse?

blood pumping through arteries, which causes them to stretch

What is pericardium?

a fluid-filled membrane that encases the heart to prevent friction

What is the septum?

a wall within the heart that seperates the left and right sides

Is the human cardiac system a closed or open system?

closed (blood flows within blood vessels)

What kind of muscle is the heart composed of?

myogenic and striated cardiac muscle

What are the atria of the heart?

top chambers that receive blood

What are the ventircles of the heart?

bottom chambers that pump blood out of the heart

What do valves in the heart do?

seperate the different chambers and prevent blood backflow

What valves are between the artia and ventricles?

atrioventricular (tricuspid on right, bicuspid on left) valves

What are the chordae tendonae?

tendons that support the atrioventricular valves

What valves do blood pass when leaving the ventricles?

semilunar valves

What is the largest artery?

the aorta

What does the aorta do?

connects to the left ventricle, carried oxygenated blood, and many major arteries branch off of it

Where do the pulmonary arteries transport blood to?

the lungs

What does the superior vena cava do?

receives deoxygenated blood from the top half of the body

What does the inferior vena cava do?

receives deoxygenated blood from the lower half of the body

What do the coronary arteries do?

supply the heart with oxygenated blood

What is angina?

the chest pain produced by a heart attack

What is a coronary bypass?

removing a patients leg vein and grafting it to the heart

What is cardiac catheterization?

a catheter is passed to an artery through the groin and moved to the aorta. A dye is injected into the catheter which can reveal a blockage in the heart when dye travels through blood vessels. this is shown on a flourescent screen

What is an angioplasty?

a procedure that puts a catheter into a blocked blood vessel to open it up

What is myogenic muscle?

muscle that contracts without external nerve stimulation

What is the sinoatrial (SA) node?

a node made up of nerves and muscle located in the right atrium that sets the heart's beat rate

What is a pacemaker?

an device that acts as an artificial sinoatrial node

What is the atrioventricular (AV) node?

a node located at the bottom of the right atrium that passes nerve impulses sent by the SA node to the Purjinkie fibers

What are Purjinkie fibers?

fibers in the bottom of the heart that receive signals from the AV node and cause the ventricles to contract

What controls heart rate?

autonomic nerves

What does the sympathetic nervous system do?

controls "fight, flight, and freeze" reactions, speeds up heart rate, and increases blood pressure if it is low

What 3 things can increase heart rate?

stress, exercise, and caffeine intake

What does the parasympathetic nervous system do?

brings the body back to a state of calm, slows heart rate, and lowers blood pressure if it is high by dilating blood vessels

What things contribute to the "lubb" sound of the heart?

ventricular contraction and the closing of the AV valves

What things contribute to the "dubb" sound of the heart?

ventricles relax (filling with blood) and the opening of the AV valves

What is systole?

the state of the heart when ventricles are contracted

What is diastole?

the state of the heart when the ventricles are relaxed

What is the fuction of an electrocardiograph?

monitors electrical activity of the heart

What does the first wave (p wave) on an electrocardiograph record?

atrial contraction

What does the large spike/second wave (qrs wave) on an electrocardiograph record?

ventricular contraction

What does the final wave (t wave) on an electrocardiograph record?

ventricle recovery

What causes heart murmurs?

blood leaks past a closed heart valve (usually an AV valve) due to an improper seal which causes a gurgling sound

How can heart murmurs be detected?

with a stethoscope

Hwo does the heart compensate for valve defects?

heart beats faster and eventually enlargens

What is foxglove and what is it used for?

it is a garden plant that is used to prevent heart attacks

What is nitoglycerin used for?

heart attack prevention

What are beta-blockers?

medication that is given to people with irregular heart beats or high blood pressure to block to effects of epinephrine

What is another name for epinephrine?

adrenaline

What are beta-receptors?

receptors that receive adrenaline

Where is the beta-1 beta-receptor found and what does it do?

it is found on the surface of the cardiac muscle and affects the speed and strength of heart contractions and influences blood pressure

Where is the beta-2 beta-receptor found and what does it do?

it is found in blood vessels and bronchioles and acts to slow heart rate and lower blood pressure

What happens to blood pressure as blood moves further away from the heart?

blood pressure decreases with distance

What is cardiac output?

the amount of blood pumped from the heart each minute (strong heart\= low cardiac output, weak heart\= high cardiac output)

What is stroke volume?

the quantity of blood pumped with each heart beat, measured in ml/beat (strong heart\= high stroke volume, weak heart\= low stroke volueme)

What is blood pressure measured with?

a sphygmomanometer, which contains a cuff and an air bladder

What two typed of blood pressure does a sphygmomanometer measure?

systolic and diastolic

What two things determine blood pressure?

cardiac output and arteriolar resistance

What are the effects of epinephrine?

arteriolar constriction to digestive system and kidneys, arteriolar dilation to heart, skin, and muscles

What are the effects of the sympathetic nerve system?

arteriolar constriction everywhere except in skeletal and cardiac muscle

What are the effects of acid (lactic/carbonic acid) accumulation from exercise?

arteriolar dilation

What are the effects of CO2 accumulation?

arteriolar dilation