Topic 6 of 8 · Form 6
Homeostasis and control
Negative feedback; thermoregulation; control of blood glucose (insulin, glucagon, second messengers – cyclic AMP; diabetes); the kidney (ultrafiltration, selective reabsorption, loop of Henle, ADH and osmoregulation).
Notes for this topic 1 file, in order
Create a free account to download PDFs.
Homeostasis
Negative feedback; thermoregulation; control of blood glucose (insulin, glucagon, second messengers – cyclic AMP; diabetes); the kidney (ultrafiltration, selective reabsorption, loop of Henle, ADH and osmoregulation).
Control and coordination in mammals
Neurones; resting and action potentials; transmission along myelinated axons (saltatory conduction); refractory period; cholinergic synapses; sensory receptors; muscle contraction (sliding filament theory: actin, myosin, troponin, tropomyosin, calcium ions, ATP).
Hormonal control
Endocrine glands; the menstrual cycle hormones (FSH, LH, oestrogen, progesterone); contraceptive pills.
Control in plants
Rapid responses (Venus fly trap); auxin and cell elongation; gibberellins and seed germination; abscisic acid and stomatal closure.
Worked example: Explain why an action potential travels in one direction only.
The region behind the action potential is in its refractory period, so it cannot be depolarised again immediately.
Check yourself
- Which hormone increases the permeability of the collecting duct to water?
- What role do calcium ions play in muscle contraction?
- How does abscisic acid help plants survive drought?
Show answers
- ADH.
- They bind to troponin, moving tropomyosin to expose myosin-binding sites on actin.
- It triggers stomatal closure, reducing water loss.
Questions about this topic (0)
No questions about this topic yet.
Sign in or create a free account to join in.