Exam3Lec4Endocrinology Flashcards
What is the endocrine system?
A system of hormone-secreting glands (adrenal, heart, hypothalamusm kidneys, ovaries, pancreas, pineal, pituitary, testes, thyroid, etc) that regulate and coordinate body functions
What controls the body’s mechanisms for sensing and responding to many biologic cues and signals in order to control and maintain its internal environment (homeostasis)?
The endocrine system
The endocrine system works with what other system?
The neural system
List the major endocrine organs and where they are located
- Hypothalamus (brain)
- Pineal body: behind/ between the 2 ventricles in the cerebrum (brain)
- Pituitary: sits in the sella tunica (brain)
- Thyroid/Parathyroid (larynx): sits in ant neck
- Heart
- Thymus??
- Adrenal gland: sits above kidney
- Kidney
- Pancreas: sits partially in duodenum
- Ovary
- Testes
What are common things you see in all endocrine glands?
NO ducts, but lots of vascularization b/c they secrete into the blood system
Why do we have a endocrine vs exocrine glands?
B/c the hormones that are being secreted from the endocrine glands have to go throughout the body and exocrine glands have ducts just to go to specific sites
Do we have ducts in endocrine system?
NO
have a vascular system
What is the difference between steroid hormone and peptide hormone?
For a steroid hormone: the receptor is at the nucleus For a peptide hormone: the receptor is on the surface (cell membrane)
steroid:derived from cholest and can penetrate thru cell membrane and bind directly to nucleus and activate mRNA transcription
peptide:proteins binds to cell membrane and goes thru a secondary messenger system to evoke a physiological response
Where is the hypothalamus located and what does it contain?
located in brain and contains neurons that produce hormones
cell bodies are in hypothalamus and this is where hormones are produced
What is the function of the hypothalamus?
Regulation of the pituitary gland
* axons travel down the pituitary stalk and synapse in the post pit gland to store hormones and activates release via NT
* Connections to the portal system (network of cappilaries) allow the hypothamus to stimulate the ant pituitary galnd to release hormones
Where do the axons from the hypothalamus extend into?
Extend down into the posterior pit. (pituitary stalk and synpase in the post pit)
What is the pituitary infundibular stalk?
Where axons of the hypothal pass through and where the portal system for ant pit passes thru
Are hormones made in the hypothalmus or posterior pit?
cell bodies are in hypothalamus and this is where hormones are produced. Post pit stores and secretes these hormones (vasopressin and oxy)
Explain how hormones are released with the ant pit.
The hypothal produces releasing hormones. These releasing hormones go into the secretory system and then go into the ant pit and stimulate the release of hormones
Where do we have a portal system and why is is necessary?
We have it in the ant. pit and we need it b/c we need a system with 2 capillary beds.
1 bed in the hypothalmaus to pick up the releasing hormones and distrubute to the vessels in the ant pit.
Another capillary bed to get to thru the tissues and stimulate cells to release hormones and then go back into the system and released to the body.
What are 2 other names for the ant pit?
adenophysis and pars distalis
What is another name for the post pit?
Pars nervosa
What two structures are similar in structure to the ant pit?
Pars tuberalis and Paras intermedi
Pars tuberalis: wraps around the infundibular stalk
Posterior pituitary:
* What does it not do?
* What does it contain?
* What does it secretes?
- DOES NOT produce its own hormones -> hypothalmus does then send the hormones down to store
- Herring bodies store hormones from the hypothalamus
- Secretes vasopressin (ADH)+ oxytocin
What are the three main types of cells secreted by the ant pit?
- Acidophils
- Basophils
- Chromophobes
Basophils and acidophils=chromophils
What are the 2 types of acidophils of the ant pit and what hormones do they release into the blood?
- Somatotropes-> GH
- Lactotropes->Prolactin (PRL)
GH, PRL
chromophils; stain pink
What are the 3 types of basophils of the ant pit and what hormones do they release into the blood?
- Thyrotropes: Thyrotropin (TSH)
- Gonadotropes: Follitropin (FSH) or Luteotropin (LH)
- Corticotropes: Corticotropin (ACTH), Melanocyte, Stim hormone (MSH)
TSH, ACTH, FSH, LH, MSH (all SH and a TH)
chromaphils-stains purple/ blue
Anterior pit:
* What does it do?
* What cells and what do they release?
- Does produce own hormones
- Hormones released from cells: acidophils and basophils
- Acidophils: GH+ PRL
- Basophils: TSH+ACTH+FSH+LH
What are chromophobes?
They don’t stain, they have a clear appearance bc they released all of their secretory product so they dont have the vessels there to pick up the stain anymore
What are the hormones released at the nerve terminals from the post pit and their target tissue?
Vasopressin(ADH)-> kidney, vasculature
Oxytocin -> Mammary gland, uterus
Where is the pineal gland located, and how can this play a role clinically?
Located at the midline right between the lateral ventricles near brainstem
Used by radiologists to see if you have a brain tumor or hematoma because if they see pineal pushed to one side, there is somthing pushing the gland b/c its usually located at the midline
remember pineal gland secretes melatonin
How does the light (sun) and darkness affect the pineal gland?
Darkness stimulates the pineal gland to release melatonin. The sun depresses the pineal gland to reduce melatonin
Regulated by light:
* Daytime inhibits the pineal gland-> no melatonin
* Night time activates the pineal gland-> secretes melatonin
Anatomy of the thyroid/parathyroid. Where are they located?
Thyroid: below thyro-laryngeal cartilage. Has right and left lobe connected by the isthmus (larynx-neck region)
Parathyroid: sits behind the thyroid and has 4 glands ( 2 sup 2 inf)
Where are the precursors of the thyroid hormone stored? What occurs after its stored?
Precursors are stored in the colloid and then they are iodinated extracellularly, then secreted
Thyroid consists of ____ containing ____ and ____ cells.
follicles, prinicpal (follicular), parafollicular (c-cells)
What are principal cells?
Principal cells also called Follicular cells are cells that produce and secrete thyroid hormones (T3 + T4)
What are parafollicular cells?
These are c-cells and these produce/secrete calcitonin
Antagonist towards parathyroid (PTH)
Role in regulating Ca secretion
The _ acts as antagonist by secreting calcitonin from c cells to work against PTH
thyroid
What regulates the thyroid? How?
Regulated by iodide:
1. Iodide gets transported into the colloid (lumen) of the follicle
2. In the colloid, iodide generates thyroid hromone precursors
3. Presursors get transported out of the colloid and into the follicular cells
4. In the follicular cells, thyroid hormone (T3/4) is produced and secreted
A decrease in fxn of the thyroid gland can lead to what?
Goiter (enlarged thyroid gland)
due to a lack of iodine resulting in decr T3/T4
Which type of cell(s) is produced by the parathyroid hormone? And what is its function?
- Chief cells: secrete parathyroid hormone (PTH)
- Oxyphil cells: inactive chief cells -> appear as big, pink, puffy cells
Parathyroid gland:
* location?
* Cells present?
* Function?
- located behind the thyroid gland
- Chief cells and oxyphil cells
- regulating blood Ca levels
What is the fxn of the adrenal gland?
To maintain balance of ions (Na+, K+, and glucose) and produce sex hormones
The hormones produces by the adrenal gland has what percursor? What organelle do you see the most?
Cholesterol/Steroid precursor. See lots of smooth ER
What does the adrenal medulla make?
Norepi and epi
MEN
What are the layers if the adrenal cortex and name the hormones they produce.
- Zona Glomerulosa-> aldosterone
- Zona fasiculata-> cortisol
- Zona Reticularis-> androgens
sweet, salty, sex
all are steroid hormones
Which zones are arranged in a ball conformation and which is arranged in a cord conformation?
Zona Fasiculata: cord like arrangement
Zona Reticularis and and Glomerulus: ball like arrangement
What does the exocrine and endocrine pancreas produce ?
Exocrine: digestive enzymes
Endocrine: islets of langerhans-> beta cells-> insulin alpha cells-> glucagon
What is the difference between the base and apical surface of the acinar cells?
Base: has lots of rough ER-> stains purple
Apical surface: stores proteins/enzymes-> stains pink
Key features to identify each of the following structures below
1. Pineal gland
2. Parathyroid
3. Thyroid
4. Adrenal gland
5. Post Pituitary
6. Ant pic
- Pineal gland: brain sands
- Parathyroid: Oxyphils
- Thyroid: Colloids
- Adrenal gland: 3 zona
- Pituitary: herring bodies
- Ant pit: acido and basophils
brain sand: calcified concretions that increase with age
