Hormones
What gland produces insulin
Pancreas
What is the effector in the knee-jerk reflex
Quadriceps muscle
What does ADH stand for
Antidiuretic Hormone
What is the small gap between two neurons called?
Synaptic Cleft
Which two body systems coordinate homeostasis?
Nervous & Endocrine
Which hormone increases blood glucose by stimulating glycogen breakdown
Glucagon
Which type of neuron connects sensory and motor neurons in the spinal cord?
Interneuron
Where is ADH released from
Posterior pituitary
Which part of the neuron receives signals from other neurons?
Dendrites
Give one similarity and one difference between hormones and neurotransmitters.
similarity: both are chemical messengers.
Difference: hormones travel in blood, neurotransmitters cross synapses
Name the hormone produced by the adrenal medulla during “fight or flight"
Adrenaline/Epinephrine
Reflexes are described as “involuntary.” What does this mean?
They occur without conscious brain involvement
How does ADH affect the kidney’s collecting ducts?
Makes them more permeable to water → more water reabsorbed
What ion enters the axon during depolarisation
Na+
In osmoregulation, which organ is the main effector?
Kidneys
What is the difference between steroid and peptide hormones in terms of how they act on target cells?
steroids pass through membranes; peptides bind to surface receptors and trigger second messengers
Why are reflexes faster than voluntary actions?
Shorter neural pathway, bypass brain, fewer synapses = less synaptic delay
What triggers ADH release?
High blood osmolarity detected by hypothalamus osmoreceptors
How does myelin increase the speed of nerve impulse transmission, and what is the name of this process?
Myelin insulates the axon so the action potential jumps between the nodes of Ranvier instead of moving continuously. This is called saltatory conduction, and it greatly increases the speed of transmission.
Explain how adrenaline and noradrenaline prepare the body for “fight or flight.”
Increase heart rate, breathing, blood glucose, redirect blood to muscles, etc.
Explain the role of thyroxine in metabolism
Increases metabolic rate
What is this pathway describing?
Stimulus → photoreceptor → sensory neuron → interneuron → motor neuron → effector (eyelid muscle)
blink reflex
Why does drinking a large volume of water reduce ADH secretion, and what effect does this have on urine production
Drinking excess water lowers blood osmolarity. Osmoreceptors in the hypothalamus detect this change and signal the pituitary to reduce ADH release. With less ADH, the kidney’s collecting ducts become less permeable to water, so less water is reabsorbed, resulting in large volumes of dilute urine.
Explain the role of calcium ions in synaptic transmission
They enter the presynaptic terminal, trigger vesicles to fuse and release neurotransmitter into cleft
During dehydration, how do the nervous and endocrine systems work together to maintain homeostasis?
Osmoreceptors in the hypothalamus (nervous system) detect increased blood osmolarity. The hypothalamus then signals the posterior pituitary (endocrine system) to release ADH. ADH travels in the blood to the kidneys, making the collecting ducts more permeable so water is reabsorbed, restoring fluid balance.