Lab 01: Endocrine Anatomy and Histology Overview

Hypothalamus

Links endocrine and nervous systems, regulates hormones.

Pituitary Gland

located in the sella turcica of the sphenoid bone; Master gland controlling other endocrine glands; Anterior is epithelial; posterior is glial cells.

Pineal Body

Produces melatonin, regulates sleep-wake cycles.

Thyroid Gland

Produces thyroid hormones, regulates metabolism.

Follicles produce TH; parafollicular cells secrete calcitonin; Two lobes connected by isthmus, anterior surface- secretes TH and calcitonin; extremely vascular and metabolically active

Parathyroid Gland

Regulates calcium levels, located behind thyroid.

Densely packed epithelial cells secrete PTH.

Thymus

Site of T-cell maturation, active in infants.

Adrenal Glands

Sit atop kidneys, produce steroid hormones; composed of cortex and medulla.

Pancreas

Mixed functions, produces insulin and glucagon.

Gonads

Ovaries and testes, produce sex hormones.

Hormones

Chemical signals released into the bloodstream.

Target Tissues

Cells with receptors for specific hormones.

Downregulation

Decreased sensitivity of target tissues to hormones.

Adenohypophysis

Anterior pituitary, secretes various hormones; connected to the hypothalamus via a portal system

Infundibulum

Stalk connecting hypothalamus to pituitary gland.

Hypothalamohypophyseal Portal System

Blood vessel system linking hypothalamus and pituitary.

Growth Hormone (GH)

Stimulates growth and protein synthesis in tissues.

Prolactin (PRL)

Stimulates milk production in mammary glands.

Thyroid Stimulating Hormone (TSH)

Stimulates thyroid gland to produce hormones.

Adrenocorticotropic Hormone (ACTH)

Stimulates adrenal cortex to secrete hormones.

Neurohypophysis

Posterior pituitary, nervous tissue; releases hormones from hypothalamus that come by the hypothalamohypophyseal tract to terminate here and release their chemical products as needed

Tropic Hormones

Hormones targeting other endocrine glands.

Chemical Signals

Includes amino acids, proteins, and steroids.

Follicle Stimulating Hormone (FSH)

Stimulates follicle maturation and estrogen secretion.

Luteinizing Hormone (LH)

Triggers ovulation and testosterone synthesis.

Antidiuretic Hormone (ADH)

released from posterior pituitary; Regulates water retention in kidneys.

Oxytocin

Stimulates uterine contractions and milk ejection; released from posterior pituitary

Thyroid Hormone (TH)

Regulates metabolic rate via T3 and T4.

Calcitonin

Lowers blood calcium by inhibiting osteoclasts.

Parathyroid Hormone (PTH)

Increases blood calcium by stimulating bone breakdown.

Zona Glomerulosa

Produces mineralcorticoids like aldosterone.

Zona Fasciculata

Produces glucocorticoids like cortisol.

Zona Reticularis

Produces sex hormones, including androgens.

ADH Deficiency

Leads to diabetes insipidus and copious urination.

Hypothyroidism

Can cause myxedema or cretinism.

Hyperthyroidism

Can lead to Grave's disease.

Osteoporosis

Condition caused by excess PTH leading to weak bones.

Nephrons

Kidney structures targeted by ADH for water reabsorption.

Follicles in Thyroid

Cuboidal cells that produce and store thyroid hormones.

Parafollicular Cells

Secrete calcitonin between thyroid follicles.

HPA Axis

Hypothalamic-pituitary-adrenal axis regulating stress response.

CRH(Corticotropin-releasing hormone)

Corticotropin-releasing hormone from hypothalamus.

Cortisol

Glucocorticoid hormone increasing energy metabolism.

Glucocorticoids

Steroid hormones affecting metabolism and immune response.

Aldosterone

Mineralcorticoid regulating sodium and water balance.

Mineralcorticoids

Hormones controlling electrolyte balance in kidneys.

Adrenal Medulla

Inner part of adrenal gland secreting catecholamines.

Epinephrine

Hormone triggering fight or flight response.

Norepinephrine

Hormone enhancing alertness and blood flow.

Pancreas

Mixed gland producing hormones and digestive enzymes.

Insulin

Hormone increasing glucose uptake by cells.

Glucagon

Hormone stimulating glucose release from liver.

Islets of Langerhans

Pancreatic cells secreting insulin and glucagon.

Acinar Cells

Pancreatic cells producing digestive enzymes.

Estrogen

Female hormone regulating reproductive functions.

Progesterone

Hormone preparing uterus for pregnancy.

Testosterone

Male hormone promoting secondary sex characteristics.

Histology of Endocrine Glands

Study of microscopic structure of hormone-producing glands.

Sympathetic ANS

Autonomic nervous system activating fight or flight response.

inhibiting hormones

hormones that inhibit the anterior pituitary from releasing hormones