Chapter 13: Haemostasis and Human Urinary System

Question 1

regulation of blood glucose level

Answer 1

• control by alpha and beta cells in pancreatic cells

Alpha cells secret insulin

• stimulate muscle cells use glucose in cell respiration
• stimulate conversion of excess glucose into glycogen stored in liver and muscle cells
• in adipose tissue, excess glucose is convert into fats

Beta cells secret glucagon

• stimulate the conversion of glycogen into glucose
• promote break down of fat into fatty acid for metabolic process to generate energy

Question 2

regulation of partial pressure of carbon dioxide

Answer 2

• During vigorous activity, partial pressure of CO2 will increase due to cellular respiration.
• CO2 dissolve in blood plasma to form carbonic acid.
• Carbonic acid broken down into H+ ions and bicarbonate ions.
• pH value of blood and cerebral fluid decresase.
• detected by central chemoreceptor in medulla oblongata and peripheral chemoreceptor in neck (carotid body and aortic body)
• nerve impulse is triggered and sent to respiratory control centre and cardiovascular control centre in medulla oblongata
• intercoastal muscle, diaphragm and cardiac muscle contract and relax quickly.
• rate of ventilation, heartbeat, and breathing increase.
• more CO2 is expel out of lungs during exhalation.

Thus, partial pressure of carbon dioxide and blood pH return to normal.

Question 3

Regulation of blood pressure

Answer 3

Blood pressure drop due to serious blooding,

• baroreceptor in carotid artery and aortic arch is less stimulated
• cardiovascular control centre in medulla oblongata is less stimulated
• vasoconstriction occur
• resistance of blood flow in bloodstream increase
• cardiac muscle contract stronger
• blood pressure increase to normal

Blood pressure raise due to vigorous activity,

• baroreceptor in carotid artery and aortic arch is stimulated
• cardiovascular control centre in medulla oblongata is stimulated
• vasodilation occur
• resistance of blood flow in bloodstream reduced
• cardiac muscle contract weaker
• Blood pressure decrease to normal

Question 4

function of kidney

Answer 4

• control total volume of fluid in body
• control concentration of ions in body
• control blood osmotic pressure
• control electrolyte content and pH value of blood and body fluids

Question 5

functional unit of kidney

Answer 5

nephron

Question 6

5 steps in formation of urine`

Answer 6

1. ultrafiltration
2. reabsorption at PCT
3. reabsorption at LOH and DCT
4. secretion
5. urine formation

Question 7

how ultrafiltration occur

Answer 7

• large diameter of afferent capillary than efferent capillary create high hydrostatic pressure
• high pressure force almost all the blood components out of glomerulus capillaries into Bowman’s capsule except macromolecules and red blood cells
• the product form is called glomerular filtrate

Question 8

explain reabsorption

Answer 8

In Proximal convoluted tubule,

• 100% of glucose and amino acid is actively absorbed via active transport
• sodium ions is actively pumped while chloride ions is passively transport into blood capillaries network
• difference in concentration of solute cause water to enter into blood capillaries via osmosis

In Loop of Henle,

• water is absorbed via osmosis
• sodium ions are reabsorbed via active transport

In Distal convoluted tubule,
- amount of water and salt absorbed depends on content of water and salt in blood

Question 9

secretion

Answer 9

• most active in distal convoluted tubule
• opposite of reabsorption
• occurs through simple diffusion and active transport
• substances secreted include K+, Na+, NH4+, creatinine, urea and some drugs

Question 10

formation of urine

Answer 10

• remaining renal fluid reach collecting ducts called urine
• small amount of fluid will diffuse into surrounding fluid due to small molecular size
• urea contain creatinine, uric acid, water and NaCl
• flow through ureter, bladder, urethra
• excreted out of body

Question 11

regulation of blood osmotic pressure

Answer 11

Drinking too less water,

• increase blood osmotic pressure
• osmoreceptor in hypothalamus stimulated
• pituitary gland stimulated to secrete ADH
• water permeability of wall of DCT and collecting duct increase
• more water absorbed from renal fluid into blood capillaries
• urine is concentrated and low in volume
• thus, blood osmotic pressure return to normal

Drinking too much water,

• blood osmotic pressure decrease
• osmoreceptor in hypothalamus less stimulated
• pituitary gland is less stimulated to secret less ADH
• wall of DCT and collecting duct is less permeable to water
• less water is reabsorbed from renal fluid into blood capillaries
• urine is diluted and high in volume
• thus, blood osmotic pressure return to normal

Question 12

compositions of kidney stone

Answer 12

• uric acid
• calcium oxalate
• crystalline calcium phosphate