The Circulatory System

Question 1

Coronary Circulation

Answer 1

(Coronary - Heart)
•supplies the heart itself with oxygenated blood

Question 2

Pulmonary Circulation

Answer 2

(Pulmonary - Lungs)
•carried deoxygenated blood to the lungs for gas exchange

Question 3

Systemic Circulation

Answer 3

•carries oxygenated blood to all parts of the body

Question 4

Blood

Answer 4

•plasma (55%), white blood cells and platelets (<1%), and red blood cells (45%)

Question 5

Plasma

Answer 5

•fluid in which blood cells are suspended
•mostly water (over 90%)
•plasma with fibrinogen and other clotting factors removed is called serum

Question 6

Dissolved in Plasma

Answer 6

•glucose, amino acids, fats, vitamins, ions, metabolic waste products, gases (O2, CO2), hormones, proteins: albumin (regulated osmotic pressure); globulins (e.g., antibodies); fibrinogen (clotting factors)

Question 7

Plasma pt.2

Answer 7

•plasma also carries dissolved ions (e.g., Na+, K+, Ca2+, Cl-, HCO3- (bicarbonate)
•increase [Na+] in plasma= increase water in blood stream= increase blood volume= increase pressure
•high salt diets can lead to high blood pressure (hypertension)

Question 8

Leucocytes (White Blood Cells)

Answer 8

•general function: body defense and immunity
•types:
Granulocytes: neutrophil, basophil, eosinphils - particles/grains
Agranular: lymphocytes, monocytes

Question 9

Granulocytes

Answer 9

•a type of white blood cell that has small granules (grains/particles) in cytoplasm (Neutrophil, Eosinophil, Basophil)
•functions: (immediate) immune responses, act quickly in response to infections, especially bacterial and fungal, by releasing their granule to destroy pathogens or signal other immune responses

Question 10

Neutrophils

Answer 10

Function:
•”first responders” in immune defense
•primary role in identifying and destroying bacteria and fungi
•release enzymes to attack and digest pathogens
•first to arrive - at injury or infection sites to clear pathogens

Question 11

Basophil

Answer 11

Function:
•”immune surveillance” ability to help detect and destroy some early cancer cells
•release the histamine in their granules during an allergic reaction or asthma attack
•release enzymes to improve blood flow and prevent clots

Question 12

Eosinphils

Answer 12

Function:
•specialized defense against parasites
•release toxic proteins and reactive oxygen species to break down parasites and infected cells

Question 13

Agranulocytes

Answer 13

Function:
•primarily involved in adaptive (long-term) immune responses
•help the body remember and react more effectively to specific pathogens
•monocytes also play a role in innate (immediate) immunity by phagocytizing pathogens and presenting antigens to activate other immune cells

Question 14

Monocytes/Macrophages

Answer 14

•large, irregular nucleus
•function as phagocytes
•macrophages are monocytes that migrated from bloodstream into body tissue
•many leucocytes use phagocytosis to destroy bacteria or harmful substances
•phagocytosis: engulf harmful substance, enzymes released to destroy substance and leucocytes, remnants (white blood cell and cellular debris) as pus, may be seen at site of cut or pimple

Question 15

Lymphocytes

Answer 15

•two types: B-lymphocytes and T-lymphocytes
•these cells react to exposure to antigens by producing proteins
•B-cells produce and secrete their proteins as antibodies
•T-cells produce and “wear” their proteins in their membrane. Memory Cells of past Infections
•in both cases, they neutralize the specific antigens for which they were made

Question 16

Erythrocytes (Red Blood Cells)

Answer 16

•erythroblasts in marrow undergo mitosis
•one new cell becomes another erythroblast, the other becomes a red blood cell
•as it matures, it produces large amounts of hemoglobin until the nucleus is squeezed out of the cell
•life span is 120 days, when they eventually break apart and are removed by the liver and spleen
•function: gas exchange

Question 17

Formed Elements

Answer 17

•cells and cell parts
•produced in bone marrow
•all blood cells lose their ability to reproduce when they differentiate
•when they die, they are replaced by more blood cells that are produced in bone marrow

Question 18

Platelets

Answer 18

•small, disc-shaped cell fragments
•function: blood clotting

Question 19

Blood Clotting

Answer 19

•plasma contains numerous chemical clotting factors, and two clotti proteins: prothrombin and fibrinogen
•when a vessel wall is damaged, the clotting factors are activated
•these clotting factors cause prothrombin to combine with Ca2+ to form thrombin
•thrombin causes fibrinogen (normally soluble and globular) to change into fibrin (insoluble and threadlike)

Question 20

Blood Clotting pt. 2

Answer 20

•meanwhile, collagen changes the platelets’ surface to become sticky
•platelets clump together, stick to the damaged vessel wall and plug the wound
•fibrin threads join the plug to form a web-like network to form the clot

Question 21

Arteries

Answer 21

•carry blood away from the heart
•aorta is the largest blood vessel in the body
•aorta-arteries-arterioles (smallest artery with smooth muscle wall)
•signals from nerve can regulate diameters of arterioles and control blood flow to certain parts of the body

Question 22

Arteries pt. 2

Answer 22

•can withstand high blood pressure; thick, muscular, elastic walls
•when blood is pumped, arteries expand slightly in diameter to accommodate increased pressure
•outer lateral of arteries has elastin fibres to give elasticity
•after contraction, arteries return to normal
•inner layer endothelium: a single layer of smooth cells reduce friction with moving blood
•arteries are located deep within the body

Question 23

Vasodilation

Answer 23

an increase in the diameter (dilation) of arterioles that increases the blood flow to tissues

Question 24

Vasoconstriction

Answer 24

a decrease in diameter (contraction) that decreases blood flow

Question 25

Veins

Answer 25

•carry blood to the heart
•lie closer to the body’s surface
•venules - veins
•thin, elastic, collapsible walls
•like arteries but have a thinner layer of smooth muscles cells
•since pressure is reduced, veins have a system of valves to prevent the back flow of blood
•blood moves through the veins by skeletal muscle contraction and some blood pressure

Question 26

Capillaries

Answer 26

•as arteries branch and get smaller, their muscle layer becomes thinner until is disappears altogether all that remains is the endothelium
•the diameter of the vessel also decreases, so that blood cells must pass through in single file
•capillaries cover a large area for material exchange
•no cell is further than 50 um from a capillary

Question 27

Exchange of Materials

Answer 27

•materials diffuse from capillaries into surrounding tissue through pores in the vessel walls
•these pores are too small to allow large stuff through, so only small molecules, ions and water can pass through these pores
•this mixture creates a solution called interstitial fluid
•materials are exchanged between the cell and the extracellular fluid
•the fluid then re-enters the capillaries and is carried away by veins (and some by lymph vessels)

Question 28

Control of the Heart Beat pt. 1

Answer 28

The SA node fires an impulse. The impulse spreads through the walls of the right and left atria, causing them to contract. This forces blood into ventricles.

Question 29

Control of the Heart Beat pt. 2

Answer 29

The impulse travels to the AV (atrioventricular) node

Question 30

Control of the Heart Beat pt. 3

Answer 30

The impulse travels through a pathway of fibers called the HIS- Purkinje network. This network sends the impulse into the ventricles and causes them to contract. This forces blood out of the heart to the lungs and body.

Question 31

Control of the Heart Beat pt. 4

Answer 31

The SA node fires another impulse. This cycle begins again

Question 32

Heart Beat

Answer 32

•the medulla oblongata receives stimuli and sends massages along two nerves that end at the heart’s S/A nodes:
•The vagus nerve (parasympathetic) releases a chemical (acetylcholine) that inhabits the S/A node
•The accelerator nerve (sympathetic) releases noradrenaline that stimulates the S/A node
•the combined effects of these two antagonistic nerves, controlled by the brain, regulate the correct heart rate as needed by the body

Question 33

Heart Beat pt. 2

Answer 33

•so the heart is regulated to pump out enough blood to provide oxygen and nutrients needed by the body at any given time
•arteries also help in the distribution of blood by dilating or constricting, based on the needs of specific organs (ie. whether they are currently active or not)

Question 34

Cardiac Output

Answer 34

•the volume of blood pumped by the heart each minute
•average resting cardiac muscle output: males-5.6 L/min females-4.9 L/ min
•maximum cardiac output: trained-25 to 40 L/min untrained-15-20 L/min

Question 35

Homeostasis: The Control of Heart Rate During Exercise

Answer 35

Muscle Action Increases:
•increased cellular respiration, increased [CO2] blood- increased blood acidity, stimulates medulla oblongata
•medulla stimulates accelerator nerves, noradrenaline released on the S/A node, heart muscle contractions increase in rate and strength, increased cardiac output to lungs and body, more O2 picked up and delivered

Question 36

As exercise ends

Answer 36

•decreased cellular respiration, decreased [CO2] blood
•feedback to medulla oblongata that less O2 is needed, but blood is still under high pressure
•medulla oblongata stimulates vagus nerve, acetylcholine released on the S/A node, heart muscle contractions decreased, cardiac output and blood pressure decrease

Question 37

Heart Continuation

Answer 37

•heart removed from living animal and continued to beat
•if someone is brain dead, they can still have a beating heart
•cardiac muscle is myogenic, which means it can contract and relax without input from external nerve stimuli. The rate of contraction and relaxation is adjusted by nervous system

Question 38

Blood Pressure

Answer 38

•each ventricular contraction caused a surge of blood through the arteries: pulse
•this exerts an increased pressure on the walls of the arteries: blood pressure
•the pressure changes:
•systolic pressure: pressure during ventricular contraction
•diastolic pressure: pressure during ventricular relaxation
•blood pressure is expressed as a comparison of both numbers: systolic pressure (over) diastolic pressure
•measured by sphygmomanometer