Nervous and Endocrine Systems Review

Comprehensive practice flashcards covering the anatomy, physiology, and homeostatic mechanisms of the nervous and endocrine systems based on the lecture transcript.

What is the definition of homeostasis?

The body’s attempt to adjust to a fluctuating external environment to maintain a constant internal balance or steady state.

What are the two main divisions of the human nervous system?

The central nervous system (CNS), consisting of the brain and spinal cord, and the peripheral nervous system (PNS), which relays information between the CNS and the rest of the body.

What are the three essential parts found in all neurons?

Dendrites, a cell body, and an axon.

How does the myelin sheath affect nerve impulses?

It acts as insulation for the neurons and speeds up the movement of nerve impulses by allowing them to jump between the nodes of Ranvier.

What are the three categories of neurons based on their function?

Sensory neurons (afferent), interneurons (association), and motor neurons (efferent).

What are the five essential components of a reflex arc?

The sensory receptor, the sensory neuron, the interneuron, the motor neuron, and the effector.

What is the typical value for a neuron's resting membrane potential?

$$-70\,mV$$

What process restores the original polarity of the nerve membrane after depolarization?

Repolarization, where potassium channels open and $K^+$ ions diffuse out of the cell.

What is the all-or-none response in neurons?

The principle that neurons either fire maximally or not at all once a threshold level of stimulus is reached.

What is a synapse?

A small region or space between neurons, or between neurons and effectors, across which neurotransmitters carry a chemical message.

What enzyme is released to destroy acetylcholine and allow a neuron to recover?

Cholinesterase.

What are the three layers of the meninges surrounding the brain?

The dura mater (outer), arachnoid mater (middle), and pia mater (inner).

What is the function of the cerebellum in the hindbrain?

It controls limb movements, balance, and muscle tone.

Which part of the brain coordinates many nerve and hormone functions and maintains internal equilibrium?

The hypothalamus.

What are the two divisions of the autonomic nervous system?

The sympathetic nervous system (prepares for stress) and the parasympathetic nervous system (restores resting levels).

What is the function of the lens in the human eye?

It focuses the incoming image onto the retina.

What is the difference between rods and cones in the retina?

Rods respond to low-intensity light and detect black and white, while cones identify color and require high-intensity light.

What condition is caused by a buildup of aqueous humour increasing pressure in the eye?

Glaucoma.

What are the three tiny bones (ossicles) in the middle ear?

The malleus (hammer), incus (anvil), and stapes (stirrup).

Where is the organ of Corti located and what is its function?

It is located in the cochlea of the inner ear and acts as the primary sound receptor.

How do the endocrine system and nervous system differ in their control mechanisms?

The nervous system enables quick adjustments to environmental changes, while the endocrine system maintains control over a longer duration.

What are the two hormones produced by the islets of Langerhans in the pancreas?

Insulin (lowers blood sugar) and glucagon (raises blood sugar).

What is the difference between Type 1 and Type 2 diabetes?

Type 1 occurs when the pancreas cannot produce insulin due to beta cell degeneration; Type 2 is associated with decreased insulin production or ineffective insulin use.

What hormones are produced by the adrenal medulla and the adrenal cortex in response to stress?

The medulla produces epinephrine and norepinephrine; the cortex produces glucocorticoids (like cortisol) and mineralocorticoids (like aldosterone).

What disorder is caused by an enlargement of the thyroid gland due to iodine deficiency?

Goiter.

What hormone is produced by the parathyroid glands to raise blood calcium levels?

Parathyroid hormone (PTH).

Where is Antidiuretic Hormone (ADH) synthesized and where is it stored?

It is synthesized in the hypothalamus and stored in the posterior pituitary lobe.

What is the primary function of aldosterone?

It increases sodium retention and water reabsorption by the kidneys to help maintain body fluid levels and blood pressure.

What are prostaglandins?

A group of hormones produced by most cells in response to damage that act locally to stimulate inflammation, blood flow, and pain perception.