Topic 15: Control and Coordination Flashcards
Definitions I:
(a) Hormone
(b) Neurone
(c) Synapse
(a) Hormone: Chemical signal from glands. (1 mark)
(b) Neurone: Nerve cell transmitting impulses. (1 mark)
(c) Synapse: Junction between neurones. (1 mark)
Describe the endocrine system’s features with ADH in a dehydrated human. [2 Marks]
ADH from pituitary targets kidneys (1 mark); Regulates water via blood (1 mark). (2 marks)
In a dog, compare nervous and endocrine system coordination. [3 Marks]
Nervous: Fast, electrical impulses (1 mark); Endocrine: Slower, hormones in blood (1 mark); Both coordinate responses (1 mark). (3 marks)
Draw and label a motor neurone from a spinal cord diagram. [2 Marks]
Long axon, dendrites, cell body (1 mark); Label: axon, myelin (1 mark). (2 marks)
In a human eye, outline the role of sensory receptor cells. [2 Marks]
Receptors detect light (1 mark); Stimulate impulses in sensory neurones (1 mark). (2 marks)
In a taste bud, describe an action potential sequence in a sensory neurone. [3 Marks]
Chemoreceptor detects taste (1 mark); Na⁺ enters, depolarises (1 mark); Action potential fires (1 mark). (3 marks)
Explain how a resting potential is maintained in a motor neurone. [2 Marks]
Na⁺/K⁺ pump maintains -70mV (1 mark); K⁺ leaks out, rests (1 mark). (2 marks)
In a myelinated neurone, explain saltatory conduction during a reflex. [3 Marks]
Myelin speeds impulse (1 mark); Jumps nodes, saltatory (1 mark); Faster reflex (1 mark). (3 marks)
Explain the refractory period’s role in impulse frequency in a pain signal. [2 Marks]
Refractory limits firing rate (1 mark); Ensures distinct impulses (1 mark). (2 marks)
Describe a cholinergic synapse’s function in a brain signal. [3 Marks]
Acetylcholine released, Ca²⁺ triggers (1 mark); Binds receptors, depolarises (1 mark); Signal crosses synapse (1 mark). (3 marks)
In a biceps muscle, explain neuromuscular junction roles in contraction. [4 Marks]
Junction releases acetylcholine (1 mark); T-tubules spread signal (1 mark); Sarcoplasmic reticulum releases Ca²⁺ (1 mark); Contracts muscle (1 mark). (4 marks)
Relate sarcomere ultrastructure to function in a leg muscle micrograph. [3 Marks]
Sarcomere: Actin/myosin bands (1 mark); Shortens for contraction (1 mark); Z-lines anchor (1 mark). (3 marks)
In a sprint, explain the sliding filament model of muscle contraction. [4 Marks]
Ca²⁺ binds troponin, moves tropomyosin (1 mark); Myosin binds actin (1 mark); ATP powers sliding (1 mark); Muscle shortens (1 mark). (4 marks)
Describe the Venus fly trap’s rapid response to prey touch. [2 Marks]
Hairs trigger action potentials (1 mark); Lobes snap shut fast (1 mark). (2 marks)
In a pea shoot, explain auxin and gibberellin roles in growth. [4 Marks]
Auxin pumps H⁺, elongates cells (1 mark); Gibberellin breaks DELLA (1 mark); Activates growth genes (1 mark); Stem elongates (1 mark). (4 marks)
