Homeostasis and Endocrine Systems Review

Study Notes

Homeostasis Review

Homeostasis is the maintenance of a stable internal environment.
Feedback loops are crucial to homeostasis. Negative feedback loops counteract changes, while positive feedback loops amplify them.
The nephron is a functional unit of the kidney responsible for filtering blood and forming urine.
Aquaporins are proteins that regulate water movement across cell membranes.
The kidneys, along with other organs, play a role in maintaining homeostasis.
Thermoregulation is the process of maintaining body temperature.
Ectotherms regulate their body temperature externally, while endotherms regulate it internally.
Osmoregulation is the regulation of water and solute balance in an organism.
Nitrogenous waste, produced by humans, is primarily excreted as urine.
Urinalysis can detect various conditions and illnesses.
Proteinuria, or protein in the urine, often indicates kidney damage.
Caffeine can increase urination.

Endocrine System

The endocrine system uses hormones to regulate body functions.
Major endocrine glands include the anterior, posterior, and pituitary glands.
Hormones act on target tissues or organs.
Synthetic hormones may be necessary in cases of hormone deficiency.
Exocrine glands secrete substances onto surfaces (e.g., sweat glands), unlike endocrine glands which secrete hormones directly into the bloodstream.
Hormones bind to receptors, influencing cellular activities.
Two methods of hormone receptor binding include direct interaction and second messenger systems.
The adrenal glands regulate various body functions, including stress response.
The parathyroid gland regulates calcium levels.
The pineal gland produces melatonin, influencing sleep-wake cycles.
Testosterone is a natural hormone crucial for male development and function.
Epinephrine (adrenaline) is released into the bloodstream causing diverse physiological effects depending on the target tissue.
Hormones can induce multiple effects on different parts of the body.

Nervous System

The nervous system has two main divisions: central and peripheral.
The nervous system regulates communication and responses to external stimuli.
Neural pathways facilitate communication between the brain and other parts of the body.
The reflex arc describes the path of a simple, automatic response to a stimulus.
The myelin sheath insulates axons, increasing the speed of nerve impulses.
Nodes of Ranvier contribute to the rapid propagation of nerve impulses.
A chemical synapse involves neurotransmitter release, whereas an electrical synapse is direct ionic coupling.
A refractory period is the time after an action potential when a neuron can't fire another action potential.
The resting membrane potential is the electrical potential difference across a neuron's membrane when it's not firing.
Threshold potential is the critical level of depolarization needed to trigger an action potential in a neuron.
White matter consists of myelinated axons, and gray matter contains neuronal cell bodies and dendrites.
The blood-brain barrier regulates the passage of substances into the brain.
The sympathetic and parasympathetic nervous systems work together to regulate various functions.
Afferent neurons carry information to the brain, while efferent neurons carry information away from the brain.
Neurons are specialized cells which facilitate communication between different parts of the body.
Membrane potential changes in neurons can result from the flow of ions, enabling the transmission of signals.
Nociceptors are sensory receptors that detect pain.
The nervous system significantly relies on salts for proper function.