The basics
The term for maintaining a relatively constant internal environment despite changes in the internal and external environment.
What is homeostasis?
The type of neuron that transmits impulses FROM sensory receptors TO the CNS.
What is a sensory neuron?
The cells in the Islets of Langerhans that release insulin when blood glucose is too high.
What are beta (β) cells?
The gland that sits on top of the kidneys and releases adrenaline during a fight or flight response.
What is the adrenal gland?
The organ in the brain that acts as the thermoregulatory centre, monitoring blood temperature.
What is the hypothalamus?
The three types of homeostatic mechanisms available to an organism.
What are structural, physiological, and behavioural mechanisms?
The fatty coating formed by Schwann cells that wraps around some axons and speeds up nerve conduction.
What is the myelin sheath?
The process by which the liver converts excess glucose into glycogen for storage.
What is glycogenesis?
The division of the autonomic nervous system activated during fight or flight — responsible for "mobilising the body for action."
What is the sympathetic nervous system?
The process where arterioles supplying the skin narrow in cold conditions, reducing blood flow to the surface and decreasing heat loss.
What is vasoconstriction?
The normal range for blood pH, and what the condition is called when blood pH drops below this range.
What is 7.35–7.45, and what is acidosis?
The six steps that occur at a synapse between the arrival of an electrical impulse and the generation of a new impulse in the next neuron.
What are: impulse arrives at pre-synaptic terminal → neurotransmitter released from vesicles → diffuses across synaptic cleft → binds to receptors on post-synaptic membrane → ion channels activated → new electrical impulse generated → neurotransmitter broken down by enzymes?
The reason insulin cannot be taken as an oral tablet by Type 1 diabetics.
What is that insulin is a protein hormone and would be digested in the gastrointestinal tract before reaching the bloodstream?
The two ways adrenaline directly raises blood glucose levels in the body.
What are stimulating glycogenolysis in liver cells (breaking glycogen into glucose) and inhibiting insulin secretion from beta cells?
The term for the mechanism by which hairs stand on end in cold conditions, trapping an insulating layer of air close to the skin surface.
What is hair erection (contraction of the erector pili muscles)?
The negative feedback loop that controls blood CO₂ and pH — name the three receptor sites involved and the effector organs that respond.
What are the medulla oblongata, carotid bodies, and aortic bodies — and the intercostal muscles, diaphragm, heart, and blood vessels?
The neurotransmitter linked to Parkinson's disease, and the reason patients experience tremor and slowed movement.
What is dopamine — and Parkinson's is caused by progressive loss of dopamine-producing neurons in the brain, removing the signal that coordinates smooth voluntary movement?
The three-level hormonal cascade that controls thyroxine secretion — name the glands, hormones, and the direction of the negative feedback.
What is: hypothalamus releases TRH → anterior pituitary releases TSH → thyroid releases thyroxine — and rising thyroxine levels feed back to suppress TRH and TSH release?
Hormone released during activation of fight or flight, the type of receptor, where it binds, what process it triggers and what molecule is released from that process.
What is: adrenaline binds to protein receptors on the liver cell membrane (cell membrane receptors — it is water soluble), triggering a signalling cascade that activates glycogenolysis, converting stored glycogen into glucose which is released into the blood?
The four simultaneous responses the body produces when blood temperature rises above 37°C, and the mode of transmission (nervous or hormonal) for each.
What are: sweating (nervous), vasodilation (nervous and hormonal), hairs lying flat (nervous), and reduced metabolic rate via decreased thyroxine and adrenaline (hormonal)?
This patient's blood pH of 6.9, breathing rate, and the molecule responsible for the drop.
What is acidosis caused by excess CO₂ dissolving in blood to form carbonic acid, with an elevated breathing rate attempting to expel CO₂ and restore pH?
These are the three ways a sensory, interneuron, and motor neuron differ in structure and location relative to the CNS.
What are: sensory neurons have the cell body offset mid-axon with dendrites outside the CNS and a short axon entering it; interneurons have all components inside the CNS with short axons; motor neurons have the cell body and dendrites inside the CNS but a long axon extending out to effectors?
These are the mechanism, cause, and management that distinguish Type 1 from Type 2 diabetes.
What are: Type 1 is autoimmune destruction of beta cells causing zero insulin production, managed with injections; Type 2 is insulin resistance in body cells with eventual beta cell exhaustion, caused by lifestyle factors and managed with diet, exercise, and medication?
These are the two systems involved in fight or flight, the order in which they act, and why hormones are needed after the nervous system fires.
What are the nervous system (acts first — hypothalamus activates the sympathetic NS immediately) and the endocrine system (acts second — sympathetic NS stimulates adrenal medulla to release adrenaline), with hormones needed to sustain and amplify the response beyond what nerve signals alone can maintain?
These are two examples each from the cold and hot responses that prove thermoregulation cannot be purely nervous.
What are: cold — shivering is nervous but increased thyroxine secretion is hormonal; hot — sweating is nervous but decreased adrenaline/thyroxine to reduce metabolic rate is hormonal — proving both systems must act together?