Endocrine System and Blood Physiology Lecture Exam 1

Flashcards defining core vocabulary for endocrine system functions, hormone types, and blood components based on Lecture Exam 1 notes.

Hormones

Chemical messengers that travel through the blood to tell organs and tissues what to do and when, controlling vital processes like metabolism, growth, reproduction, sleep cycles, mood, and stress responses.

Up-regulation

The process where a cell or body system increases its quantity of cellular components such as RNA, proteins, or receptors to become more sensitive to an external signal.

Down-regulation

A biological or physiological process where a cell or the nervous system decreases its response or the quantity of a component in response to an external stimulus.

Local Hormones

Chemical messengers that act on nearby cells without entering the bloodstream.

Circulating Hormones

Chemical messengers secreted by endocrine glands directly into the bloodstream.

Autocrine

A type of cell communication where a cell releases a chemical messenger that binds to receptors on its own surface to trigger a response.

Paracrine

A form of cell signaling where a cell releases signaling molecules that travel short distances through the extracellular fluid to affect nearby target cells.

Steroids

A broad class of organic compounds and artificial hormone drugs that either reduce inflammation in the body or promote muscle growth.

Water-Soluble and Lipid-Soluble Hormones

Hormone categories that differ in their chemical structure, how they travel, where they bind, and how long their effects last.

Antagonistic Effect

An effect that occurs when two or more substances, drugs, or chemicals combine and their total combined effect is less than the sum of individual effects.

Endocrine Gland Stimuli

The three major types of stimuli that cause endocrine glands to release hormones: humoral, hormonal, and neural.

Hypothalamus

The brain region that controls the release of hormones from the anterior pituitary gland.

Human Growth Hormone (HGH)

The primary hormone associated with body growth, also known as Somatotropin.

Prolactin

The primary hormone responsible for making breast milk.

Oxytocin

A secondary hormone stored and released by the posterior pituitary gland that is responsible for releasing milk.

Cortisol

A glucocorticoid hormone secreted by the adrenal glands.

Corticosterone

A weaker glucocorticoid hormone secreted by the adrenal glands.

Aldosterone

A mineralocorticoid hormone secreted by the adrenal glands.

Posterior Pituitary Gland

A gland that stores and releases only two hormones: oxytocin and antidiuretic hormone (ADH), also known as vasopressin.

Parathyroid Hormone (PTH)

A hormone that primarily regulates the levels of calcium in the blood, while playing a key role in managing phosphorus (phosphate) blood levels and activating vitamin D.

Insulin

The primary hormone that lowers blood glucose levels.

Glucagon

The primary hormone released by the pancreas in response to a decrease in blood glucose.

Endocrine Glands

Ductless organs that produce and release hormones directly into the bloodstream to regulate vital body functions.

Blood

A vital fluid making up $7\%$ to $8\%$ of human body weight, consisting of about $55\%$ liquid plasma and $45\%$ blood cells, with a slightly basic pH of $7.35$ to $7.45$, a bright red color when carrying oxygen, and a higher thickness than water.

Hematocrit

A blood test that measures the percentage of total blood volume made up of red blood cells.

Blood Plasma

The liquid portion of blood containing approximately $90\%$ to $92\%$ water.

Hematopoiesis

The biological process by which the body creates new blood cells and platelets.

EPO (Erythropoietin)

A natural hormone produced mainly by the kidneys that stimulates the bone marrow to make red blood cells.

Red Blood Cells (RBC)

Cells that carry oxygen from the lungs to the rest of the body and take carbon dioxide back to the lungs to be exhaled.

Platelets

Tiny fragments in the blood that stick together to form clots and stop bleeding upon injury.

Leukocytosis

A high total white blood cell count that can be caused by severe allergic reactions or bad allergy flare-ups.

Eosinophils

A specific type of white blood cell that swarms, traps, and destroys parasitic worms by releasing powerful toxic chemicals.

Granular White Blood Cells

White blood cells containing sacs filled with chemicals to kill germs.

Agranular White Blood Cells

White blood cells that lack visible chemical sacs.

Four Steps of Blood Clot Formation

The protective body process that stops bleeding in damaged blood vessels, consisting of: 1. Vascular Spasm (Constriction), 2. Platelet Plug Formation (Primary Hemostasis), 3. Coagulation (Secondary Hemostasis), and 4. Fibrinolysis (Clot breakdown).