Chapter 15- Homoestasis

Question 1

Define ectotherms

Answer 1

Use surroundings to warm their bodies and are heavily dependent on environment

Question 2

Define endothermic

Answer 2

Control own body temp and doesn’t rely on environment

Question 3

Define vasodilation

Answer 3

The arterioles near the surface of the skin dilate when the temperature rises

Question 4

Define vasoconstriction

Answer 4

The arterioles near the surface of the skin constrict.

Question 5

Define excretion

Answer 5

Is the removal of the waste products of metabolism from the body

Question 6

The main metabolic waste products in mammals are:

Answer 6

Carbon dioxide- one of waste products of respiration excreted from the lungs
Bile pigments- formed from the breakdown of haemoglobin from old red blood cells in the liver. They are excreted in the bile from the liver into the small intestine via gall bladder and Bile duct they colour the faeces
Nitrogenous waste products- formed from the breakdown of excess amino acids by the liver. All mammals produce urea as their nitrogenous waste. Fish produce ammonia while birds and insects produce uric acid. Urea is excreted by the kidneys in the urine

Question 7

What vessels supplies oxygenated blood

Answer 7

Hepatic artery

Question 8

What vessel returns blood back to heart

Answer 8

Hepatic vein

Question 9

What other vessel supplies blood to liver

Answer 9

Hepatic portal vein

Question 10

What is the ornithine cycle?

Answer 10

Removing the amino group from the amino acid and converting the highly toxic ammonia to the less toxic and more manageable compound urea.

Question 11

What is the kidney made up of?

Answer 11

Medulla
Cortex
Pelvis

Question 12

Role of cortex

Answer 12

The cortex is the dark outer layer. This is where the filtering of the blood takes place and it has a very dense capillary network carrying the blood from the renal artery to the nephrons

Question 13

Role of the medulla

Answer 13

Lighter in colour- it contains the tubules of the nephrons that form the pyramids of the kidney and collecting ducts

Question 14

Pelvis function

Answer 14

Central chamber where the urine collects before passing out down the ureter

Question 15

Structure of the nephron

Answer 15

Bowmans capsule
Proximal convoluted tubule
Loop of henle
Distal convoluted tubule
Collecting duct

Question 16

Structure of bowmans capsule

Answer 16

Cup shaped structure that contains the glomerulus, a tangle of capillaries. More blood goes into the glomerulis than what leaves it due to ultrafiltration

Question 17

Structure of proximal convulated tubule

Answer 17

The first, foiled region of the tubule after the bowmans capsule, found in the cortex of the kidney. This is where many substances needed by the blood are reabsorbed

Question 18

Structure of loop of henle

Answer 18

A long loop of tubule that creates a region with a very high solute concentration in the tissue fluid deep in the medulla. The descending loop runs down from the cortex through the module to a hairpin bend at the bottom of the loop. The ascending limb travels back up through medulla to cortex

Question 19

Structure of distal convoluted tubule

Answer 19

A second twisted tubule where the fine tuning of water balance of the body takes place. The permeability of walls to water vary in the response to ADH.

Question 20

Structure of collecting duct

Answer 20

The urine passes down the collecting duct through the medulla to the pelvis. More fine tuning of water balance takes place

Question 21

Define Ultrafiltration

Answer 21

Removal of nitrogenous waste and osmoregulation of the blood is ultrafiltration.

Question 22

Define Reabsoprtion

Answer 22

Ultrafiltration removes urea, the waste product of protein breakdown.

Question 23

What is reabsorbed in The proximal convoluted tubule?

Answer 23

All of glucose, amino acids , vitamins and hormones are moved from the filtrate back into the blood by active transport

Question 24

Where are podocytes found

Answer 24

Bowmans capsule

Question 25

Which part of the nephron are the walls impermeable to water?

Answer 25

Ascending limb of loop if henle

Question 26

Where is glucose reabsorbed back into the blood?

Answer 26

Proximal convulated tubule

Question 27

Where does ADH act on the walls?

Answer 27

Collecting duct

Question 28

Where is most of the water reabsorbed into the blood?

Answer 28

Proximal convulated tubules

Question 29

Where cells detect a decrease in water potential

Answer 29

Walls of blood vessels in hypothalamus

Question 30

Name the cells that detect this decrease in water potential

Answer 30

Osmoreceptors

Question 31

What pressure does the glomerulus have

Answer 31

A high hydrostatic pressure

Question 32

Regions present in cortex

Answer 32

Proximal convulated tubule
Bowsmans capsule
Distal convulated tubule

Question 33

Where does detoxification occur

Answer 33

Licer

Question 34

An example of detoxification in the liver

Answer 34

Catalase breaks down hydrogen peroxide into oxygen and water

Question 35

Define homeostasis

Answer 35

Maintaining a constant internal environment even through a constantly changing environment

Question 36

Hameodialysis

Answer 36

Blood leaves patients body via an artery and flows into the machine, where it flows between partially permeable dialysis membranes. These membranes mimic the bowmans capsule. Dialysis fluid picks up the waste products and urea is removed. Clean blood flows through bubble trap to get rid of bubbles.

Question 37

How are molecules reabsorbed in the proximal convoluted tubule?

Answer 37

Via ATP