Circulatory System

Question 1

why do we need a circulatory system?

Answer 1

most multicellular organisms have a transport system
- plants: xylem and phloegm
- animals: circulatory systems

reason?
- simpler organisms can obtain nutrients and dispel waste in a direct exchange with their environment
- multicellular organisms are too large to do this, they need a transport system to bring substances to and away from all cells

Question 2

what is blood made of (the circulatory system transports blood)

Answer 2

plasma: contains dissolved nutrients, hormones, waste, etc
platelets: perform blood clotting
white blood cells: body’s immune system
red blood cells: transport oxygen & carbon dioxide

Question 3

heart

Answer 3

double pump, ventricles forcefully push blood out with enough pressure to get the blood through the arteries

Question 4

arteries

Answer 4

• large blood vessels which carry blood AWAY from the heart
• the blood is under high pressure
• with the exception of the pulmonary arteries, they carry oxygenated blood to the body’s tissues

Question 5

veins

Answer 5

• large blood vessels which carry blood TO the heart
• the blood is under low pressure, veins contain valves to ensure that the blood doesnt flow backwards
• with the exception of the pulmonary veins, they carry deoxygenated blood to the heart from the bodys tissues

Question 6

capillaries

Answer 6

• very small narrow blood vessels (diameter 0.001mm)
• just fits red blood cells through
• walls are one cell thick
• where materials exchanges take place. thinness of capillary walls make diffusion in and out of bloodstream possible

Question 7

what are the two circulation routes + explain

Answer 7

pulmonary circulation:
- the right side of the heart pumps blood to the lungs to oxygenate the blood
- it immediately returns to the heart

systemic circulation:
- the left side of the heart pumps blood to the body to deliver oxygen and nutrients to the cells

Question 8

villi

Answer 8

• specialized for absorption in the small intestine
• thin wall, one cell thick = shorter diffusion path
• large surface area = efficient absorption of fatty acids + glycerol into the blood stream

Question 9

hepatic portal system

Answer 9

• veins that carry blood from capillaries of the stomach to capillaries in the liver
• part of the body’s filtration filter
  main function: deliver de-oxygenated blood to the liver so it can return to the heart

Question 10

desribe hepatic portal vein / superior mesenteric vein / inferior mesenteric vein / gastrosplenic vein

Answer 10

hepatic portal vein: main vein connected to liver
inferior mesenteric vein: takes blood from the colon + rectum and connects with the portal vein
superior mesenteric vein: drains blood from the samll intestine and connects w portal vein
gastrosplenic vein: formed by the union of the splenic vein from the spleen and the gastric vein from the stomach

Question 11

how do the urinary and cardiovascular systems work together

Answer 11

urinary sys = cleans blood in the circulatory sys

Question 12

how does the cardiovascular sys help maintain homeostasis

Answer 12

blood flow must be redirected continually to the tissues to maintain homeostasis