Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

28 Cards in this Set

  • Front
  • Back
Endocrine System
*Communicate information (via hormones). The hormones are carried to their destinations via:
- connective tissue spaces
- vascular tissue

- coordinates most endocrine function

*Three main classes:
1. steroids
2. small peptides, proteins, glycoproteins
3. amino acid analogues and derivatives
two main classes of hormone receptors
1. Cell Surface Receptors:
- hormones cell impermeant (can't penetrate cell membrane) (ex: peptide hormones or catecholamines)
- second messanger pathway (cAMP, IP3, DAG, calcium channels. These are small intracellular molecules that amplify the signal)

2. Intracellular receptors (target inside of cell):
- mainly nuclear
- hormones cell permeant (can easily penetrate both plasma and nuclear membranes)(steroids and thyroid hormones)
- gene expression
Major Endocrine Organs
*Pituitary gland (hypophysis)
*Pineal gland
- both of these glands are in the brain
*Thyroid gland
*Parathyroid glands
*Adrenal glands
Pituitary gland (hypophysis)
- located under hypothalamus
- Two Components (it's bilobed):
1. Anterior (adenohypophysis)
- portion of Pars Distalis
- glandular
- ectodermal (Rathke's pouch)

2. Posterior (neurohypophysis):
- portion of Pars Nervosa
- neural secretory
- neuroectoderm (infundibulum)
Pituitary gland development
-both of these portions come from distinct portions of the embryo

- comes from ectoderm of pharynx (Rathke's pouch)

- comes from neuroectoderm (infundibulum)
Pituitary gland blood supply
Two Sets:

1. Superior hypophyseal arteries:
- from internal carotid and posterior communicating artery
- two capillary beds (fenestrated): primary capillary plexus and secondary capillary plexus

2. Inferior hypophyseal arteries:
- internal carotid arteries
- supplies pars nervosa (most of the anterior lobe of the pituitary gland has no direct arterial supply)

*break into 3 capillary beds which spread the hormones throughout the body
Hypothalamo-hypophyseal system (hypothalamus + pituitary)
Three sites where hormones enter capillary beds:

1. Secretory neurons- hypothalamus

2. Dorsal/Ventral Medial and Infundibular

3. Pars distalis (anterior pituitary)
Anterior Pituitary Gland- Pars Distalis
- cords of epithelial cells with interspersed capillaries
- cells arranged in cords with capillaries
- these cells respond to signals from the hypothalamus and synthesize and secrete a number of pituitary hormones
Pars Distalis Cells
- growth hormones (GH)
- prolactin (promotes mammary gland development; initiates milk formation)

- Adrenocorticotrophic hormone (ACTH)
- Melanocyte-stimulating hormon (MSH)
- Thyroid-Stimulating Hormone (TSH)
- FSH and LH

- six main groups of hormones being produced by two classes
Pars Tubularis
*funnel-shaped region
*the pars tubularis surrounds infundibulum (wraps around it- it is an extention of the anterior lobe)
*highly vascularized (lots of capillaries)
- Hypothalmohypopyseal system
*cells are arranged in cords
*secrete gonadotropins (FSH and LH- this is the site where these are produced)
Pars Intermedia
*surrounds small cystic crypts that represent the residual lumen of Rathke's pouch (Rathe's rudiment)
*Parenchymal follicle cells
*Unknown function? Rudiment?
*Cortiocotroph cells
- MSH produced?
Posterior Pituitary (neurohypophysis)
1. Pars nervosa
2. Infundibulum

-The posterior pituitary is NOT an endocrine gland
- storage site (for neurosecretions)
Posterior Pituitary- Pars Nervosa
*Neural lobe of pituitary gland
- 100K nonmyelinated neurosecretory axons and nerve endings
- Unique axons (b/c they don't synapse with anything)

*Herring bodies (vessels)- they are collections of neurosecretory granules (dilated portions of the axon near the terminals)

*Pituicytes (like astrocytes; supportive cells of the posterior pituitary neurons)

*Hormones (2):
1. Antidiuretic hormone (ADH)- H2O regulation
2. Oxytocin- stimulates mammary gland cells to eject milk and stimulates contraction of smooth muscle during pregnancy
Adrenal Gland
*Superior to the Kidney
*3 regions:
- capsule (outer dense CT)
- cortex (steroid secreting portion)
- medulla (catecholiamine-secreting portion)

- a lot of blood vessels running into adrenal gland all over
- vein drains medulla
Adrenal Cortex
*Three Regions:
- Zona Glomerulosa
- Zona Fasciculate
- Zona Reticularis
Zona Glomerulosa
-15% of cortical volume; most distal

*the cells of glomerulosa secrete mineralocorticoids (regulate Na and K homeostasis and water balance)
- secretes aldosterone
Zona Fasciculata
-65%; middle

*cells in fasciculata are large and polyhedral arranged in long cords and have high lipid content
*spongiocytes (in fasci.)- make glucocorticoids (regulate glucose and fatty acid metabolism)

- ACTH regulates secretion of the zona fasciculata
Zona Reticularis
-7%; next to medulla

*reticularis cells are smaller, stain darker, arranged in random cords, make androgens
Adrenal Gland- Medulla
*Chromaffin cells (irregular short cords):
- numerous granules
- sympathetic nerve endings
- modified nerve cells
- two hormonal products:
epinephrine (80%)
norepinephrine (NE-producing cells have larger and darker staining granules than E-producing cells)
Adrenal Gland- development
*Embryologically distinct:
- Cortex --> Mesodermal cells
- Medulla --> Neuroectodermal

*Fetal Cortex makes up 70% during gestation
Adrenal Gland- vascularization
*Three patterns:
- Capsular capillaries (supply the capsule)
- Fenestrated cortical sinusoid capillaries (supply the cortex)
- Medullary arterioles (traverse the cortex and bring arterial blood to the:
*medullary capillary sinusoids)

*Medulla- dual supply
*Central Meduallary vein

*Sponge effect- smooth muscle assoc. with these veins contracts and pushes blood out of adrenal gland (so there's a surge of hormone release. ex: adrenaline rush by this squeezing of adrenal gland)

*blood supply: from arteries directly into medulla or from cortex
Adrenal Disorders
*Cushings- adrenal hyperfunction; increase in glucocortocoids

*Addison's- hypofunction of adrenal hormones; weight loss; fatigue; darkening of skin
Pineal Gland
*Involved in both endocrine and neuroendocrine
*Neural development (from neuroectoderm)

*Two parenchymal cell types:
1. Pinealocyte (clustered cells; often have cytoplasmic extentions (secretory-types cells))

2. Interstitial (glial) cells- supportive cells

*Brain Sand (corpora arenacea)- clumps of calcium carbonate; clumps increase with aging

*Secrete melatonin (regulates reproductive function in mammals)

*Daily rhythm
Thyroid Gland
*Thin CT capsule with trabeculae
*Produce thyroxine (T4) and triiodothyronine (T3)- hormones involved in growth and development

*Follicle- functional unit
- simple epithelium
- contains colloid (gelatinous substance; precursor for hormones)

*Highly vascularized
Thyroid Gland- Cell Types
*Simple epithelium:
- Follicle cell- can store them (regulate T3 and T4)
- Parafollicle cell- in between follicles; involved in production of hormone calcitonin
Thyroid Diseases
*Hyperthyroidism- hypothermia; dry skin; puffy skin; bulging eyes
- Graves Disease (excessive amts of thyroid hormones released)

- Hashimoto's disease (autoimmune disease; low levels of circulating thyroid hormone stimulate release of excessive amounts of TSH, which causes hypertrophy of the thyroid)
*4 small glands- located on thyroid
*Derived from pharyngeal pouch
*Cells in cords
*Adipose with age
*Parathyroid Hormone: osteoclast stimulation
Parathyroid Cell Types
- Chief (secretory granules)- help regulate calcium by secreting PTH

- Oxyphil- larger cells but small number of them; they get replaced by adipose tissue over time.