Chapter 6: Transport in Humans

Question 1

Plasma

Answer 1

• yellowish liquid, contains mainly water, glucose, salts, proteins, amino acids, fats, vitamins, hormones & urea
• transports blood cells ard body
• nutrients from SM to other parts of the body
• excretory products from organs where are they produced excretory organs where they r removed
• hormones from endocrine glands to target organs

Question 2

Red Blood Cells

Answer 2

• circular, biconcave shape
• no nucleus
• contains haemoglobin
• flexible

Question 3

White blood cells

Answer 3

• phagocytes: perform phagocytosis- WBC engulfs & destroys foreign particles
• lymphocytes: recognise foreign particles, destroy bacteria & viruses, cause bacteria to clump tgt to be engulfed by phagocytes, neutralise toxins produced by bacteria

Question 4

platelets

Answer 4

• fragments of cytoplasm
• contains enzyme which catalyses fibrinogen into fibrin threads- form a network of RBCs to form a clot -> prevents excessive loss of blood & entry of harmful organisms into bloodstream

Question 5

heart

Answer 5

• relaxes, fills up with blood
• contracts, blood squeezed out with great force
• blood circulates thru blood vessels, transports blood ard body

Question 6

arteries

Answer 6

• transports oxygenated blood AWAY from heart
• thick muscular, elastic wall
  + withstand high blood pressure
  + stretch & recoil to push blood in spurts
• constrict when muscles contract, lumen becomes narrower & reduces amt of blood flowing thru
• dilate by relaxing muscles, lumen becomes wider to allow more blood to flow thru

Question 7

vein

Answer 7

• transports deoxygenated blood TOWARDS the heart
• thin muscular elastic walls (lower blood pressure compared to arteries)
• valves present, prevent back flow of blood (lbp)

Question 8

capillary

Answer 8

• transport blood from arteriole to venues
• no muscular & elastic wall, only one-cell thick
• shorter diffusion distance for substances to pass thru faster
• mixture of oxygenated & deoxygenated blood
  -bp lower than arteries but higher than veins
• absent valves

Question 9

capillary

Answer 9

• transport blood from arteriole to venues
• no muscular & elastic wall, only one-cell thick
• shorter diffusion distance for substances to pass thru faster
• mixture of oxygenated & deoxygenated blood
  -bp lower than arteries but higher than veins
• absent valves

Question 10

causes of coronary heart disease

Answer 10

• cholesterol & unsaturated fats deposited on inner surface of coronary arteries
• narrows lumen of arteries, increases blood pressure
• increases risk of blood clot in heart
• supply of blood and oxygen cut off from the heart- no oxygen, heart muscle cells might be damaged, heart attack

Question 11

risk factors of heart disease

Answer 11

• smoking
• unhealthy diet
• genetic factors
• age
• sedentary lifestyle

Question 12

reduce risk of CHD

Answer 12

• healthy diet
• don’t smoke
• regular physical exercise