Endocrine System

Endocrine System

System that communicates by means of hormones released into the bloodstream.

Nervous System

System that communicates by means of electrical impulses and neurotransmitters.

Gap Junctions

Pores in cell membranes that allow signaling molecules to pass directly between adjacent cells.

Neurotransmitters

Chemical messengers released from neurons that travel across synaptic clefts to communicate with target cells.

Paracrines

Chemical signals secreted into tissue fluids to affect nearby cells.

Hormones

Chemical messengers that travel in the bloodstream to distant organs and tissues.

Exocrine Glands

Glands that have ducts to carry secretions to an epithelial surface or digestive tract.

Endocrine Glands

Glands that release hormones directly into the bloodstream without ducts.

Hypothalamus

Region of the brain that produces hormones regulating the anterior pituitary and releases others into the posterior pituitary.

Antidiuretic Hormone (ADH)

Hormone released from the posterior pituitary that increases water retention in the kidneys.

Oxytocin (OT)

Hormone released during labor and lactation that promotes bonding and milk ejection.

Thymus

Gland involved in the development of T cells, playing roles in the endocrine, lymphatic, and immune systems.

Thyroid Gland

Largest purely endocrine gland that secretes hormones for metabolic regulation.

Thyroxine (T4)

Hormone produced by the thyroid gland that increases metabolic rate.

Calcitonin

Hormone secreted by parafollicular cells of the thyroid that lowers blood calcium levels.

Parathyroid Hormone (PTH)

Hormone secreted by the parathyroid glands that increases blood calcium levels.

Catecholamines

Hormones released from the adrenal medulla that prepare the body for physical activity.

Mineralocorticoids

Hormones from the adrenal cortex that regulate electrolyte balance.

Glucocorticoids

Hormones that regulate metabolism of glucose and other fuels, often released in response to stress.

Insulin

Hormone produced by the pancreas that lowers blood glucose levels.

Glucagon

Hormone that raises blood glucose levels by stimulating gluconeogenesis.

Somatostatin

Hormone that inhibits secretion of insulin and glucagon, regulating the digestive process.

Erythropoietin

Hormone secreted by the kidneys that stimulates red blood cell production.

Renin

Hormone secreted by the kidneys that regulates blood pressure through the renin-angiotensin system.

Leptin

Hormone secreted by adipose tissue that helps regulate energy balance and suppress appetite.

Atrial Natriuretic Peptide (ANP)

Hormone secreted by the heart that lowers blood pressure by increasing sodium and water output.

Osseous Tissue

Bone tissue that secretes osteocalcin, influencing metabolism and insulin sensitivity.

Metabolic Pathways

Biochemical processes through which substances are converted and utilized in living organisms.

Hormone Receptors

Protein or glycoprotein molecules that bind hormones and initiate cellular responses.

Second Messengers

Intracellular molecules that mediate cellular responses triggered by hormones that cannot penetrate cell membranes.

Protein Synthesis

Process through which cells produce proteins, often influenced by hormone binding.

Hypoglycemic Hormones

Hormones that lower blood glucose concentrations.

Hyperglycemic Hormones

Hormones that raise blood glucose concentrations.

Feedback Loops

Regulatory pathways through which hormone secretion is controlled.

Steroid Hormones

Hormones derived from cholesterol that can penetrate plasma membranes and affect gene expression.

Endocrine Functions of the Liver

Liver produces several hormones, including angiotensinogen and erythropoietin.

Kidneys Hormonal Role

Kidneys produce hormones that play a critical role in blood pressure regulation and calcium metabolism.

Cholecystokinin

Hormone secreted by the small intestine that stimulates digestion and regulates appetite.

Somatic Functions of Hormones

Hormones' roles in influencing growth, metabolism, and homeostasis.

Epithelial Surface

Surface layer of cells that lines the organs and structures of the body.

Colloid

Protein-rich fluid found in thyroid follicles; crucial for hormone production.

Fasciculata

Middle layer of the adrenal cortex that secretes glucocorticoids.

Osteoblasts

Bone-forming cells that secrete osteocalcin, impacting insulin regulation.

Chemical Messengers

Substances that transmit signals between cells, including hormones and neurotransmitters.

Natriuretic Peptides

Hormones that lower blood pressure and blood volume.

Vasopressin

Another name for antidiuretic hormone (ADH), associated with water retention.

Hormonal Saturation

Condition when all hormone receptors are occupied by hormone molecules.