circulatory system

Question 1

function of circulatory system

Answer 1

1. transports nutrients to other cells, carries waste away from cells
2. transports gases > O2 to cells and CO2 away from cells
3. regulates internal temperature
4. transports chemical substances vital to health from one part of body to another, carries hormones
5. protects against blood loss and against disease causing microbes/toxins in body

Question 2

what does a heart that is a myogenic muscle mean?

Answer 2

cardiac muscle is able to contract without being stimulated by external nerves

Question 3

arteries

Answer 3

• carry oxygenated blood away from the heart
• 3 layers:
  OUTER: connective tissue
  MIDDLE: elastic, smooth muscle tissue
  INNER: one cell thick
• elastic tissue; pressure created by contracting heart which pumps blood

Question 4

arterioles

Answer 4

• blood from arteries enters vessels of smaller diameter called arterioles
• most highly regulated blood vessels in body and contribute to blood pressure

Question 5

capillaries

Answer 5

• branch from arterioles to connect them to venules
• spread throughout body in fine network, surround cells
• fluid and gas exchange occur between blood and body cells
• allows RBC through in single file

Question 6

veins

Answer 6

• thinner than arteries, larger inner circumference and little muscle
• carry deoxygenated blood toward heart

Question 7

RBC (erythrocytes)

Answer 7

• specialized for transport of oxygen
• contain hemoglobin which helps carry oxygen and carbon dioxide in small amounts to aid in waste removal
• stored in spleen

Question 8

WBC (leukocytes)

Answer 8

• part of body’s response to infection
• have a nucleus and colourless
• wbc numbers double when fighting infections
  MACROPHAGES: engulf and digest
  LYMPHOCYTES: make antibodies

Question 9

plasma

Answer 9

• clear, yellowish liquid that carries cells and platelets (help blood clots)
• contain carbon dioxide, minerals, vitamins, etc.

Question 10

blood components

Answer 10

solid: rbc, wbc, platelets
liquid: plasma
- produced in bone marrow, inside bones

Question 11

platelets

Answer 11

• involved in blood clotting
• produced from larger nucleated cells in bone marrow that broke apart
• act as sealant to close wounds

Question 12

clotting process

Answer 12

• broken blood vessel release chemicals that attract platelets to injury
• platelets release chemicals that combine with plasma chemicals to produce protein called thromboplastin
• thromboplastin reacts with prothrombin to produce thrombin
• this reacts with fibrinogen to produce fibrin, acts as mesh over injury
• fibrin mesh sticks to exposed vessel wall and rbc get caught in it, causing red clot to form

Question 13

pulmonary and systemic circulation

Answer 13

PULMONARY: vessels that carry blood to/from lungs
SYSTEMIC: vessels that carry blood to/from the rest of body

Question 14

SA and AV node

Answer 14

AV (atrioventricular node): contractions from atria
- serves as conductor, passing nerve impulses via two large nerve fibres
SA (sinoatrial node): sets heart tempo/beat
- generates electrical signal that spreads over 2 atria to make them contract simultaneously

Question 15

purkinje fibres

Answer 15

• run along septum that separates right/left ventricles
  -carries impulses from AV node to bottom tip of heart

Question 16

pacemaker

Answer 16

device used to control irregular heart rhythm to 70 beats/min

Question 17

LUB DUB

Answer 17

• each time heart contracts a sound, LUB DUB, is heard
• sound caused by AV valves and semilunar valves closing in turn as blood is pushed out of heart from atria through ventricles