5.5: Animal responses

Question 1

Describe how three named components of the elbow joint interact to bring about hinge movement (bending of the arm). (3mks) f215 June 13 2b

Answer 1

1 muscles contract, in antagonistic (pairs) ; [biceps and triceps or flexor and extensor contract]
2 tendons, pull on bone / connect muscle to bone ;
3 ligaments, hold bones together / prevent dislocation ;
4 cartilage, reduces, friction / wear ;
5 synovial membrane secretes fluid ;
6 synovial fluid, is a lubricant / allows smooth movement [prevents/ reduces, friction]

Question 2

Outline the organisation and roles of the autonomic nervous system in mammals.
In your answer you should discuss the differences in physical arrangement and the differences in function, of both parts of the autonomic nervous system. (8mks)

Answer 2

1 (two parts are) sympathetic and parasympathetic ;
2 S has, short preganglionic neurone / long postganglionic neurone / ganglia near(er) spinal cord, but P has, long preganglionic neurone / short postganglionic neurone / ganglia near(er) organ [tissue];
3 S uses, noradrenaline/ norepinephrine, but P uses acetylcholine (at organ);
4 S, fight / flight / stress, but P, rest / relaxation / calm ;
5 S increases, heart rate / cardiac output / blood pressure, but P reduces this ;
6 S increases , speed / rate / depth, of breathing, but P reduces this ; [S increases ventilation rate and P slows it]
7 S increases airway diameter but P reduces it ;
8 S increases blood flow to skeletal muscle but P increases blood flow to gut (smooth muscle) ; [voluntary or striated for skeletal]
9 S for orgasm but P for sexual arousal ;
10 S dilates pupils but P constricts pupils ;
11 S makes liver release glucose, but P makes liver, store / take up, glucose ; [correct reverse reasoning for glycogen - must ref to liver]
12 P allows, peristalsis / digestion, but S reduces it ;

Question 3

State one way in which the nervous system decreases

the heart rate. f214 june13 q4bii

Answer 3

impulses along parasympathetic nerve /
impulses along vagus nerve /
nerve endings releasing acetycholine

Question 4

Name a hormone that increases the metabolic rate and so generates heat. f214 june12 q4bii

Answer 4

adrenalin(e) / thyroxin(e) / epinephrin(e)

Question 5

Outline the hormonal and nervous mechanisms involved in the control of heart rate. (5mks) f214 jan11 q5b

Answer 5

1 adrenalin(e) increases, heart rate/ stroke volume/ cardiac output;
2 cardiovascular centre in medulla oblongata;
3 nervous connection to, SAN/ sino-atrial node;
4 (which) controls frequency of waves of, excitation/ depolarisation;
5 vagus/ parasympathetic, nerve decreases heart rate;
6 accelerator/ sympathetic, nerve increases heart rate;
7 high blood pressure detected by, stretch receptors/ baroreceptors;
8 low blood pH/ increased levels of blood CO2, detected by chemoreceptors;
9 (receptors) in, aorta/ carotid sinus/ carotid arteries;

Question 6

Propioreceptor

Answer 6

a sensory receptor which receives stimuli from within the body, especially one that responds to position and movement.

Question 7

Multiple sclerosis (MS) is an auto-immune condition in which the nervous system is damaged. This damage leads to loss of sensation. One form of damage is shown in Fig. 5.2 [myelin sheath has disintegrated].
Suggest why MS is described as an auto-immune condition. f214 june10 q5ci

Answer 7

1 attacked by the body’s (own) immune system;
2 (immune system) mistakes / treats / recognises, body cells / neurones / myelin, as, ‘foreign’ / non self;
3 antibodies / (named) phagocytes / (named) B lymphocytes / (named) T lymphocytes;

Question 8

Explain why this damage leads to a loss of sensation. f214 june10 q5cii

Answer 8

1 (damage to) myelin / sheath / Schwann cell(s);
2 removes / has less, insulation;
3 interferes with / slows / stops, conduction of, (nerve) impulse / action potential or slows / stops / prevents,
saltatory conduction / described;
4 occurs, in sensory neurones / towards brain / towards CNS / from sensory organ / from receptor;