Endocrine Physiology Overview

• Physiology is the study of how living organisms function. It encompasses a wide range of processes, from the cellular level to the whole-organism level. Physiology is highly integrated, with many systems working together in concert to maintain homeostasis.

Endocrine Physiology

• Endocrine physiology focuses on the study of hormones and their effects on the body. Hormones are chemical messengers that are secreted by endocrine glands into the bloodstream, where they travel to target tissues to produce specific responses.

• Key endocrine glands include the pituitary, thyroid, adrenal, pancreas, ovaries, and testes.

• Hormones can be categorized into different groups based on their chemical structure, including peptide hormones, steroid hormones, and amine hormones. Each type of hormone exerts unique effects. For example, peptide hormones generally exert their effects by binding to receptors on the cell surface, while steroid hormones generally cross the cell membrane to interact with intracellular receptors.

• Hormonal regulation is crucial for maintaining homeostasis. This regulation is often achieved through negative feedback loops, where the response to a hormone reduces the initial stimulus causing the hormone release.

• Control of hormone secretion is complex and involves various factors, including neural input, changes in blood glucose levels, and other hormones.

• Disorders of hormone secretion can have a range of effects on the body. For example, insufficient hormone production can lead to hypothyroidism, while excessive hormone production can lead to hyperthyroidism or Cushing's syndrome. Conditions caused by endocrine dysfunction have diverse symptoms depending on the affected hormone and tissues.

Neurophysiology

• Neurophysiology is the study of the nervous system, its structure, and functions. This includes not only the workings of single neurons, but also communication between different neurons and sensory input and corresponding responses.

• Neurons are specialized cells that transmit electrical and chemical signals within the nervous system. These signals allow for the processing and communication of information throughout the body.

• Action potentials are electrical signals that travel along axons, facilitating communication between neurons. The characteristics of these potentials are crucial for understanding neural signalling. Key aspects include depolarization, repolarization, and the refractory period.

• Neurotransmitters are chemical messengers that transmit signals across the synapse, the gap between two neurons. Many different neurotransmitters exist, and each has distinct effects on target cells. Important neurotransmitters include serotonin, dopamine, acetylcholine, and GABA.

• Neural pathways describe how information travels through the nervous system. These pathways are complex and can be involved in various processes, including reflexes, perception, and cognition.

• Sensory systems in neurophysiology focus on how specialized nerve endings detect stimuli from the environment and transmit this information to the brain for processing. These form the basis of our experience of the world.

• Motor systems deal with how the brain sends signals to the muscles to produce movement. Coordinating these systems is essential for complex, controlled actions.

• Integration within the nervous system involves the complex interplay between sensory and motor signaling to achieve specific behavioral actions. This integration can involve intricate networks of neurons.

• Diseases of the nervous system are diverse and can be caused by various factors, including genetic mutations, infections, or environmental insults. Examples include Parkinson's disease, multiple sclerosis, and Alzheimer's disease. These neurodegenerative diseases and others underscore the complexity of the nervous system.