Cellular Communication and the Endocrine System

50 vocabulary flashcards covering cellular communication, homeostasis, and the endocrine system based on lecture notes.

Cellular communication

The way cells ‘talk’ to each other so the body can maintain homeostasis.

Homeostasis

A stable internal environment.

Intracellular communication

Communication that occurs within a single cell.

Intercellular communication

Communication that occurs between different cells, allowing tissues and organs to work together.

Signaling molecules

Chemical messengers such as hormones, neurotransmitters, cytokines, and growth factors used for cellular communication.

Target cells

Specific cells that have the correct receptors to recognize and bind to signaling molecules.

Receptors

Proteins that recognize and bind to specific signals, either on the cell surface or inside the cell.

Signal transduction

A chain of events inside a cell triggered by the binding of a messenger to a receptor, leading to a specific response.

Hormones

Chemical messengers produced by endocrine glands that travel through the bloodstream to target organs and tissues.

Endocrine glands

Ductless glands such as the pituitary, thyroid, and adrenal glands that release hormones into the blood.

Feedback mechanisms

Processes that detect changes in a condition or hormone levels and trigger a response to adjust the system.

Negative feedback

The most common feedback mechanism that works to keep conditions within a normal range by reversing a change.

Positive feedback

A less common mechanism that strengthens or amplifies the original stimulus until a specific endpoint is reached.

Pituitary gland

A gland at the base of the brain that releases hormones influencing other glands; sometimes called the ‘master gland.’

Thyroid gland

A gland in the neck that produces hormones that set the body’s metabolic pace, heart rate, and body temperature.

Adrenal glands

Glands located on top of the kidneys that release hormones for the stress response and blood pressure control.

Pancreas

An organ that produces insulin and glucagon to help keep blood glucose within a normal range.

Ovaries and testes

Endocrine organs that produce sex hormones supporting reproduction and secondary sex characteristics.

Water-soluble hormones

Hormones, such as peptide hormones, that usually bind to receptors on the cell membrane and use second messengers.

Second messengers

Molecules like cyclic AMP ($cAMP$) that relay a signal inside the cell for water-soluble hormones.

Lipid-soluble hormones

Hormones, such as steroids, that pass through the plasma membrane and bind to receptors inside the cell.

Insulin

A hormone produced by the pancreas that lowers blood glucose by promoting glucose uptake and storage.

Glucagon

A hormone produced by the pancreas that raises blood glucose by stimulating the liver to release glucose.

Hypothalamus

A brain region that links the nervous and endocrine systems and controls the pituitary gland.

Stress

Any stimulus that challenges homeostasis.

General adaptation syndrome

A predictable pattern of physiological changes, including alarm, resistance, and exhaustion, that helps the body cope with stress.

Alarm stage

The first stage of stress response where the body prepares for ‘fight-or-flight’ by increasing heart rate and blood pressure.

Epinephrine

Also known as adrenaline, a hormone released by the adrenal medulla during the alarm stage of stress.

Resistance stage

The second stage of stress response where the body tries to adapt and maintain function using cortisol.

Cortisol

A hormone released by the adrenal cortex that helps provide fuel by raising blood glucose during prolonged stress.

Exhaustion stage

The final stage of stress response where body resources are depleted, weakening immune function.

HPA axis

The hypothalamic–pituitary–adrenal system involved in signaling the release of cortisol.

Adrenal medulla

The part of the adrenal gland that releases epinephrine and norepinephrine for quick stress responses.

Primary endocrine disorders

Disorders that start in the endocrine gland that produces the hormone, such as the thyroid itself.

Secondary endocrine disorders

Disorders that start in the pituitary gland, which regulates other endocrine glands.

Tertiary endocrine disorders

Disorders that start in the hypothalamus, which controls the pituitary gland.

Hyperthyroidism

A condition resulting from the thyroid gland making too much thyroid hormone.

Hypothyroidism

A condition resulting from the thyroid gland making too little thyroid hormone.

Growth hormone deficiency

A secondary disorder caused by the pituitary gland not releasing enough growth hormone.

GnRH

Gonadotropin-releasing hormone, a hypothalamic hormone that controls signals to the ovaries and testes.

Metabolic rate

The pace at which the body uses energy, primarily regulated by thyroid hormones.

Adrenal cortex

The outer part of the adrenal gland targeted by the pituitary to release cortisol.

Electrolytes

Substances like sodium ($Na^+$) and potassium ($K^+$) balanced by adrenal hormones.

Oxytocin

A hormone involved in a positive feedback loop during childbirth to increase uterine contractions.

Leptin

A hormone that contributes to homeostasis by helping regulate appetite and body weight.

Cyclic AMP

A common second messenger, abbreviated as $cAMP$, used in cellular signaling.

Reflexes

Fast responses coordinated by the nervous system, distinct from the slower responses of the endocrine system.

Chemical messengers

General term for molecules like hormones used by the endocrine system to communicate.

Norepinephrine

A hormone released alongside epinephrine by the adrenal medulla for quick stress responses.

Hormone replacement

A treatment for primary endocrine disorders when hormone levels are too low.