Animals - Chapter 11

Question 1

Importance and roles of the circulatory system

Answer 1

importance = organisms with 3 germ layers need a circulatory system to service the middle layers of cells
transports nutrients, waste, hormones, heat
helps defend against invading organisms by circulating immune cells

Question 2

Open circulatory system

Answer 2

circulating fluid (hemolymph) is pumped into an interconnected system of body cavities called sinuses, where it bathes the cells directly
contraction forces hemolymph out of blood vessels through sinuses, relaxation draws hemolymph back into heart through open-ended pores

Question 3

Closed circulatory system

Answer 3

fluid (blood) is contained within a network of blood vessels
separates blood from tissues but provides a medium for diffusion of substances

Question 4

Circulatory system of a fish

Answer 4

single circuit closed circulatory system
at the gills, blood takes in oxygen from surrounding water and deposits carbon dioxide
from gills, blood circulates to the rest of the body
atrium receives collected blood and pumps it into the ventricle, which pumps it to the gills

Question 5

Two-circuit circulatory system

Answer 5

systemic circulation = circulates blood around the body to deliver oxygen, nutrients and substances, and to pick up carbon dioxide
pulmonary circulation = circulates blood to lungs for gas exchange

Question 6

Plasma

Answer 6

protein rich liquid in which the blood cells and platelets are suspended
composed of water, plasma proteins and other molecules
function = solvent, clotting, lipid transport, defence, eliminating waste

Question 7

Erythrocytes

Answer 7

red blood cells
no nucleus or mitochondria, biconcave to maximize surface area
if oxygen drops below a certain level, EPO hormone stimulates more production of red blood cells
anemia = deficiency in hemoglobin or red blood cells

Question 8

Leukocytes

Answer 8

white blood cells
formed in bone marrow and have nuclei
functions = uses phagocytosis to engulf cells and provide protection, immune response, defense against parasitic worms
concentrated in lymph nodes

Question 9

Platelets

Answer 9

fragmented red blood cells, originate as pinched off cytoplasmic fragments in bone marrow
initiate blood clotting
no nucleus
fragile and rupture over torn blood vessels

Question 10

Blood clotting

Answer 10

blood vessel breaks, releasing chemicals that attract platelets
platelets stick to collagen fibres in order to form a clot, sealing holes in the blood vessel
risk = clots can become dislodged and block the flow of blood in another part of the body

Question 11

Arteries and arterioles

Answer 11

carries blood away from the heart
usually oxygen rich, except for the pulmonary artery
3 layers of tissue = connective, smooth muscle, endothelium
walls are elastic and thick to withstand great pressure
arteries branch into smaller and smaller arterioles

Question 12

Capillaries

Answer 12

smallest vessels in our body, vast network
thin walled to promote easy diffusion of oxygen, nutrients, and carbon dioxide
flow is regulated by sphincters
there is a decrease in the rate at which blood flows when it enters the network of capillaries because the area is much larger
this occurs in order to provide more time for diffusion

Question 13

Venules and veins

Answer 13

capillaries merge into small venules, which merge into larger veins
veins carry blood towards the heart
one-way valves push blood towards heart
less smooth muscle, not elastic, thinner walls
skeletal muscles contract and help pump blood back to the heart
varicose veins = accumulation of blood in the veins, causing them to stretch

Question 14

Blood pressure

Answer 14

pressure increases if vessels get smaller (vasoconstriction), blood volume increases
pressure decreases if vessels get larger (vasodilation), blood volume decreases
measured using stethoscope and sphygmomanometer

Question 15

Types of pressure

Answer 15

systolic = ventricles begin to contract and blood is forced out of the ventricles
diastolic = ventricles begin to relax and fill with blood
healthy = 120 over 80

Question 16

Hypertension

Answer 16

high blood pressure
causes = kidney disease, medications, age (loss of vessel elasticity), diet (high in sodium)
no symptoms until dire
diet, exercise and medication can reverse hypertension

Question 17

Pulse

Answer 17

pulse = expansion of an artery in response to the increased pressure caused by the contraction of the heart
main reason for taking a pulse is to determine the heart rate

Question 18

Lymphatic system

Answer 18

roles in both circulatory and immune systems
circulatory = ensures blood volume is maintained
immune = filters bacteria and other components from the blood

Question 19

Temperature regulation

Answer 19

mammals control heat by changing the volume of blood in the skin
voluntary, controlled by the autonomic branch of the nervous system

Question 20

The heart

Answer 20

right side = circulates blood to the pulmonary circuit
left side = receives this blood and pumps it out through the systemic circuit
AV valves have chordae tendinae because they are subjected to more pressure than the semilunar valves

Question 21

Heart sounds

Answer 21

lubb = A-V valves close after atria contract
dubb = semilunar valves close after ventricles contract
heard with a stethoscope
heart murmur = inefficient blood flow and increased blood pressure

Question 22

Setting the heart’s tempo

Answer 22

myogenic muscle = not attached to nerve, ensures heart will still beat even if the nervous system is damaged
sinoatrial node = pacemaker simulates this, cluster of nerves
atrioventricular node = impulse passed to ventricles
Purkinje fibres = pass through the septum to carry rhythm, run up along each ventricle causing contraction

Question 23

Electrocardiograph

Answer 23

measures electrical signals
P wave = atrial contractions, simulated by SA node
QRS wave = ventricular contractions, simulated by AV node and Purkinje fibres
T wave = ventricle recovers

Question 24

Artery problems (aneurysm, arteriosclerosis, atherosclerosis, coronary artery disease)

Answer 24

aneurysm = bulge in an artery due to a weak spot
arteriosclerosis = hardening of arteries
atherosclerosis = type of arteriosclerosis, hardening of arteries due to plaque buildup
coronary artery disease = atherosclerosis in the coronary arteries

Question 25

Treating coronary artery disease

Answer 25

angioplasty = catheter with a balloon is inserted into femoral artery and snaked all the way to the coronary artery, balloon is expanded and stent hold the artery open
coronary bypass = section of healthy artery or vein from another part of the body is removed and put in place of blocked coronary artery

Question 26

Angina and heart attacks

Answer 26

angina symptoms = pain//tightness in chest, pain shooting down left arm, shoulder, neck
nitroglycerine vasodilates and increases blood flow to muscles
heart attack = myocardial infarction, death of cardiac muscle

Question 27

Cardiac output and stoke volume

Answer 27

cardiac output = the amount of blood pumped out by the heart in mL per min
stroke volume = the volume of blood pumped out of the heart with each heartbeat
cardiac output = heart rate times stroke volume