homeostasis

Question 1

what are some examples of negative feedback systems
in the body

Answer 1

control of blood sugar levels by insulin and glucagon, control of temperature and water balance in the body

Question 2

what are some examples of positive feedback systems in the body

Answer 2

blood clotting, oxytocin produced during childbirth

Question 3

What is meant by the term “ectotherm”?

Answer 3

An animal which depends on the environment to regulate its internal body temperature.

Question 4

What is meant by the term “endotherm”?

Answer 4

An animal that maintains a constant internal body temperature regardless of the external temperature by generating heat through metabolic processes.

Question 5

In endotherms, temperature receptors are located in which two parts of the body?

Answer 5

The skin and the hypothalamus.

Question 6

which part of the brain is involved with temperature regulation

Answer 6

the hypothalamus

Question 7

What is seen in endotherms in response to a rise in core body temperature?

Answer 7

vasodilation, sweating and lowering hair by relaxing hair erector muscles.

Question 8

What is seen in endotherms in response to a fall in core body temperature?

Answer 8

vasoconstriction, shivering and raising hair by contracting hair erector muscles.

Question 9

Define the term excretion.

Answer 9

The removal of waste products of cell metabolism from the body.

Question 10

What are the three main waste products which need to be excreted in mammals?

Answer 10

Carbon dioxide, bile pigments and urea.

Question 11

Which process in the liver removes the amine group from amino acids when breaking down excess proteins?

Answer 11

deamination

Question 12

what are the nephrons in a kidney

Answer 12

the microscopic functional units of the kidney responsible for producing urine

Question 13

What are the four main mechanisms that must occur in the nephron to convert filtrate into urine?

Answer 13

ultrafiltration, selective absorption, secretion and excretion

Question 14

What are the five main structures found in a nephron?

Answer 14

bowman’s capsule, proximal convoluted tubule, Loop of Henle, Distal convoluted tubule and collecting duct.

Question 15

what is the glomerulus and what does it do

Answer 15

the knot of capillaries found within the Bowman’s capsule, ultrafiltration

Question 16

what does ultrafiltration in the bowman’s capsule form?

Answer 16

glomerular filtrate

Question 17

which has a larger lumen, the afferent or afferent arteriole

Answer 17

afferent arteriole

Question 18

what are the main substances in glomerular filtrate

Answer 18

Urea, glucose, salt, Cl- and water

Question 19

what can’t leave the blood plasma in the bowman’s capsule

Answer 19

blood cells and large plasma proteins

Question 20

what are hepatocytes

Answer 20

in the liver, they synthesise most plasma proteins, carry out transamination and deamination, and detoxification of the blood

Question 21

what is deamination

Answer 21

braking down amino acids by removing the ammine group to produce ammonia and keto acid which can be used in cellular respiration or converted into lipids or cholesterol

Question 22

what is the ornithine cycle

Answer 22

conversion of ammonia into urea, occurs in the hepatocytes mitochondria and cytoplasm

Question 23

what are the 3 stages of the ornithine cycle

Answer 23

1. NH3, CO2, ornithine, and ATP produce citrulline and water
2. NH3, ATP and citrulline produce arginine and water
3. Arginine and water produce urea and ornithine

Question 24

what two enzymes do hepatocytes contain for the detoxification of ethanol in the blood

Answer 24

alcohol dehydrogenase, aldehyde dehydrogenase

Question 25

what is glycogenesis

Answer 25

The conversion of glucose to glycogen

Question 26

define glycogenolysis

Answer 26

the conversion of glycogen to glucose

Question 27

what is gluconeogenesis

Answer 27

the conversion of amino acids and glycerol to glucose

Question 28

what two main hormones are produced by the adrenal cortex

Answer 28

aldosterone and cortisol

Question 29

what two main hormones are secreted by the adrenal medulla

Answer 29

adrenaline and noradrenaline

Question 30

what hormone do alpha cells in the islets of Langerhans produce

Answer 30

glucagon

Question 31

which hormone do beta cells in the islets of langerhans produce

Answer 31

insulin

Question 32

where is insulin in insulin injections obtained from

Answer 32

genetically modified bacteria

Question 33

what is the blood vessel that supplies oxygenated, nutrient-poor blood to the liver

Answer 33

hepatic artery

Question 34

what is the blood vessel that supplies deoxygenated, nutrient rich-blood to the liver

Answer 34

hepatic portal vein

Question 35

what blood vessel carries deoxygenated blood out of the liver to the liver

Answer 35

hepatic vein

Question 36

how does the liver help control blood glucose concentration in the blood

Answer 36

convert glucose into glycogen

Question 37

What is the role of the hypothalamus in osmoregulation?

Answer 37

The hypothalamus contains osmoreceptors which are sensitive to changes in the water potential of the blood. They control the release of ADH by the posterior pituitary gland.

Question 38

How does ADH increase the absorption of water

Answer 38

by increasing the permeability of distal convoluted tube and the collecting duct

Question 39

How does a pregnancy test work?

Answer 39

Pregnancy tests contain monocolonal antibodies attached to coloured beads. These antibodies are complementary to hCG. When hCG is present in the urine, it binds to these antibodies and the complexes move into a new zone which contains immobilised antibodies. The complex binds to these and the coloured beads create a blue line, indicating pregnancy.

Question 40

what is the purpose of the second line of a pregnancy test

Answer 40

acts as a control

Question 41

How do doctors estimate the glomerular filtration rate?

Answer 41

They measure the concentration of creatine in the blood.