Communication & Homeostasis

Question 1

Glycogenesis

Answer 1

Converts glucose to glycogen in the cell for storage

Question 2

Glycogenolysis

Answer 2

Conversion of glycogen to glucose

Question 3

Gluconeogenesis

Answer 3

Production of glucose by converting from amino acids and fats

Question 4

Hepatocytes

Answer 4

Liver cells that perform a range of metabolic functions

Question 5

Stimulus

Answer 5

Change in the environment that causes a response

Question 6

Response

Answer 6

Change in behaviour or physiology as a result if a change in the environment

Question 7

Homeostasis

Answer 7

Maintenance of internal environment despite external changes

Question 8

Negative feedback

Answer 8

A process that brings about a reversal of any change in conditions. Ensures homeostasis

Question 9

Positive feedback

Answer 9

Process that increases any change detected by receptors

Question 10

Ectotherm

Answer 10

An organism that relies on external sources of heat to regulate body temperature

Question 11

Endotherm

Answer 11

An organism that can use internal sources of heat such as heat gained from metabolism to maintain body temperature

Question 12

Polarised membrane

Answer 12

One that has a potential difference across it. This is the resting potential

Question 13

Depolarisation

Answer 13

The loss of polarisation across the membrane as Na+ ions rush into the cell, making it less negative

Question 14

Generator potential

Answer 14

Small depolarisation caused by Na+ ions entering the cell

Question 15

Threshold potential

Answer 15

If depolarisation of the membrane reaches -50mV then an action potential is created

Question 16

Action potential

Answer 16

A depolarisation of the membrane so that the inside is more positive that the outside (+40mV)

Question 17

Resting potential

Answer 17

The difference of voltage across the neurone cell membrane while the neurone is at rest (-60mV)

Question 18

Voltage gates channels

Answer 18

Channels that allow passed of particles or ions. They have gates which respond to changes in pd across the membrane

Question 19

Local currents

Answer 19

Movements of ions along the neurone. Flow of ions is caused by an increase in concentration at one point, causing diffusion away from the region of higher concentration

Question 20

Saltatory conduction

Answer 20

Action potential jumping from one node of ranvier to the next

Question 21

Neurotransmitter

Answer 21

Is a chemical that diffuses across the cleft of the synapse to transmit a signal to the postsynaptic neurone.

Question 22

Cholinergic synapses

Answer 22

Subsides that use acetylcholine as their transmitter

Question 23

Synaptic knob

Answer 23

Swelling at the end of the postsynaptic neurone

Question 24

Acetylcholinesterase

Answer 24

An enzyme in the synaptic cleft. It breaks down acetylcholine

Question 25

All or nothing

Answer 25

The fact that a neurone either conducts an action potential or doesn't at all

Question 26

Summation

Answer 26

The way that several small potential changes can combine to produce one large change in potential difference across the membrane

Question 27

Hormones

Answer 27

Chemical messengers

Question 28

Endocrine gland

Answer 28

Gland that secretes hormones directly into the blood

Question 29

Exocrine gland

Answer 29

Secretes molecules into ducts

Question 30

Target cells

Answer 30

Possess specific receptors on their plasma membrane that is complementary to the shape of the hormone

Question 31

Adenyl cyclase

Answer 31

Receptor for many hormones, found on plasma membrane. It converts ATP to cAMP

Question 32

Pancreatic duct

Answer 32

Tube that collects all secretions from exocrine cells in the pancreas and carries fluid to small intestine

Question 33

Islets of Langerhans

Answer 33

Small patches of tissue in the pancreas that have endocrine function. Contain alpha and beta cells

Question 34

Alpha cells

Answer 34

Secrete glucagon

Question 35

Beta cells

Answer 35

Secrete insulin

Question 36

Insulin

Answer 36

Causes blood glucose to go down: 1) glucose enters cells 2) glycogenesis 3) glucose converted to fats 4) respiration increase

Question 37

Glucagon

Answer 37

Causes glucose levels to rise: 1) glycogenolysis 2) fats used in respiration 3) gluconeogenesis

Question 38

Diabetes mellitus

Answer 38

When blood glucose concentrations cannot be controlled

Question 39

Hyperglycaemia

Answer 39

When blood glucose concentration is too high

Question 40

Hypoglycaemia

Answer 40

When blood glucose levels are too low

Question 41

Stem cells

Answer 41

Unspecialised cells that can develop into any type of new cell

Question 42

Cell metabolism

Answer 42

All chemical reactions taking place in cytoplasm

Question 43

Myogenic muscle

Answer 43

Can initiate it's own contractions

Question 44

Pacemaker

Answer 44

Region of tissue in right atrium that can generate an impulse and initiate contractions

Question 45

Medulla oblongata

Answer 45

Found at the base of the brain and co ordinates all unconscious functions