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Thermostat of the body
Hypothalmus
What type of neuron carries signals from receptors to the central nervous system?
Sensory neuron
Which neuron type transmits signals from the CNS to muscles or glands?
Motor neuron
What neuron is responsible for processing information within the CNS and connecting sensory and motor neurons?
cells that produce insulin
beta cells
Which brain structure coordinates balance and smooth muscle movement?
Cerebellum
Which part of the nervous system serves as the main pathway for reflex responses and communication between brain and body?
Spinal cord
glucagon is produced by what cells
Alpha cells (pancreas)
When body temperature drops, smooth muscle in blood vessel walls contracts, decreasing blood flow to the skin and conserving heat.
Vasoconstriction
Endocrine gland found above kidneys, helps in “fight-or-flight” response to stress.
Adrenal Gland (more specifically adrenal medulla)
Cause of Type 1 diabetes
An autoimmune response where the body’s immune system destroys the insulin-producing beta cells in the pancreas.
Give one similarity and one difference between TSH and thyroxine.
Similarity: Both are hormones involved in regulating metabolism.
Difference: TSH is released from the pituitary gland to stimulate the thyroid, while thyroxine is released from the thyroid gland and increases metabolic rate in body cells.
TSH controls the thyroid.
The thyroid controls metabolism
The hypothalamus senses that the body is running too slow or too cold.
It tells the pituitary to release TSH.
TSH tells the thyroid to speed things up.
Hormone that increases glycogen hydrolysis (glycogenolysis)
Glucagon stimulates glycogen hydrolysis (glycogen → glucose) in the liver, increasing blood glucose levels.
Walk through the physiological response our body initiates when we feel cold
The Hypothalamus compares the detected temperature to the body’s normal set point (~37 °C) and initiates responses to conserve and generate heat.
Several physiological responses occur:
Vasoconstriction – Blood vessels in the skin narrow, reducing blood flow to the surface and decreasing heat loss to the environment.
Shivering – Rapid, involuntary contractions of skeletal muscles generate heat through increased cellular respiration.
Hormonal response – The hypothalamus signals the Pituitary gland, which stimulates the thyroid to release thyroxine, increasing metabolic rate and heat production.
Behavioral responses – The brain may also trigger actions such as seeking warmth or adding clothing.
What is one similarity and one difference between cytokines and calcium ions in cell communication?
Similarity:
Both act as signaling molecules that help regulate cellular responses and coordinate communication between cells.
Difference:
Cytokines are proteins that are released from cells and send messages by attaching to receptors on other cells.
Calcium ions work inside the cell by changing their amount to help pass along a signal.
1. What is the typical resting membrane potential of a neuron?
2. Which ion rapidly enters the neuron during depolarization?
3. Which ion leaves the neuron during repolarization?
4. What is the approximate threshold potential required to trigger an action potential?
5. What membrane transport mechanism maintains resting potential by pumping Na⁺ out and K⁺ in?
1. −70 mV
2. Sodium (Na⁺)
3. Potassium (K⁺)
4. −55 mV
5. Sodium-potassium pump (Na⁺/K⁺ pump)
One example for negative feedback and one for positive feedback in homeostasis
body temperature regulation and childbirth contractions