BIO 202 Lab Endocrine

Medulla of thymus

light region

capsule of thymus

outer connective tissue layer

cortex of thymus

dark blue due to being packed with maturing T cells

tonsilar crypts

lymphatic nodules

pharyngeal epithelium

white pulp

initiates immune response to blood-borne antigens

red pulp

• reservoir for red blood cells and platelets

• phagocytosis of bacteria, foreign materials, red blood cells, and platelets

lymph node

labeled lymph node

trabecula

plasma cells

found in lymphatic nodules of lymph node

germinal center

• contains activated B cells that are differentiating to plasma cells

• make lots of proteins (antibodies)

pituitary gland

• left (darker side) is anterior pituitary gland or adenohypophysis

• right (lighter side) is posterior pituitary gland or neurohypophysis

thyrohyoid muscle

red arrow

thyroid cartilage

orange arrow

left common carotid artery

green arrow

left lobe of thyroid gland

blue arrow

isthmus of thyroid gland

purple arrow

right lobe of thyroid gland

brown arrow

trachea

black arrow

thyroid gland function

• metabolism and Blood Ca2+

• largest pure endocrine gland in adults

• bilobate joined by a narrow isthmus inferiorly

What are the 2 thyroid hormones?

• thyroid hormone (TH)

• calcitonin (CT)

thyroid hormone (TH)

• Triiodothyronine T3 and T4 Tetraiodothyronine

• T3 is active form, T4 serving as a circulating pro-hormone

• increases basal cell metabolic rates, positively impacts protein synthesis and bone growth, helps with thermoregulation

• requires iodine for snythesis and release

  • prolonged low iodine levels lead to a goiter or accumulation of TH in thyroid

Calcitonin (CT)

• released when there is excess Ca2+ in the bloodstream

• stimulates osteoblasts to add Ca2+ into bones, stimulates calcification

follicle of thyroid

red arrow

follicular cells

green arrow

parafollicular (C) cells

blue arrow

stored thyroglobulin

purple arrow

parathyroid gland

• 4 small glands partially embedded in the posterior surface of the thyroid gland

• synthesizes and rleases parathyroid hormone (PTH)

parathyroid and thyroid histology

• parathyroid on bottom

• thyroid on top

parathyroid hormone (PTH)

• stimulated by low blood Ca2+

• secreted from parathyroid gland

• targets the skeletal system

• increases blood calcium levels by stimulating bone reabsorption (osteoclasts), decreasing urinary secretion, increasing Ca2+ absorption

pancreas

• an endocrine and exocrine gland

  • endocrine = 1% of function

  • exocrine = 99% of function

    • digestive secretions

• long thin body with centralized duct

pancreatic hormones

• glucagon

• insulin

• somatostatin

glucagon

• from alpha cells

• causes cells to break down their glycogen and fat stores and release them into blood

• highest levels after fasting or pronlonged exercise

insulin

• from beta cells

• causes cells to absorb glucose (and other nutrients) circulating in the bloodstream

• highest levels after a meal

somatostatin

• from delta cells

• regulates (supresses) alpha and beta cell activity

• inhibits nutrient absorption

pancreatic islet

• Islet of Langerhans

• contains endocrine cells (alpha, beta, and delta cells)

adrenal glands

• also called the suprarenal gland

• 2 layers

  • adrenal cortex (hypothalamic control)

    • outer layer, produces 3 types of hormones, corticoids

  • adrenal medulla (sympathetic NS control)

    • inner layer, produces two hormones, fight or flight

mineralcorticoids (aldosterone)

• causes the kidneys to retain Na+ and excrete K+

• retaining water

• increasing blood volume and pressure

• think mineral, think sodium

glucocorticoids (cortisol)

• causes the body to begin breaking down energy stores (sugars, fats, proteins)

• anti-inflammatory effect over prolonged secretion

• high levels detected under stress

androgens

• testosterone and estrogens

• sex hormones for each gender but found in both sexes

hormones of adrenal medulla

• epinephrine and norepinephrine

• controlled by sympathetic NS

• increases alertness

• prepares body for physical activity

• mobilizes high-energy fuels, lactate, fatty acids, glucose

• glycogenolysis and gluconeogenesis by liver boost glucose levels

  • epinephrine inhibits insulin secretion

• increase BP, HR, blood flow to muscles, airflow, and metabolism

• reduces digestion and urine production

capsule of adrenal gland

red arrow

zona glomerulosa

• yellow arrow

• secretes aldosterone

zona fasciculata

• green arrow

• secretes cortisol and androgens

zona reticularis

blue arrow

• cortisol and androgens

adrenal medulla

• black arrow

• epinephrine and norepinephrine

adrenal capsule

zona glomerulosa - aldosterone

zona fasciculata - cortisol

adrena medulla