Endocrine System Objectives Flashcards
Explain why the endocrine system is so closely related to the nervous system
The endocrine system “works in conjunction” with the nervous system.
- It’s general function is: to integrate body systems (i.e. maintain homeostasis).
- The glands are effectors/ body parts that are stimulated by motor responses from the AUTONOMIC NS.
Distinguish between an endocrine gland and exocrine gland
Endocrine Gland:Endocrine System gland that secretes hormones directly into the BLOODSTREAM; a ductless gland that runs 24/7
Exocrine Gland: NOT part of Endocrine System secretes substances into DUCTS, which leave the body (i.e. sweat/sebaceous glands), or into an internal space or lumen (i.e. digestive glands)
Define the term: Hormone
Hormone: a very powerful substance secreted by an endocrine gland into the bloodstream, that affects the function of another cell or “target cell” at a distant site.
General characteristics of a hormone
- Potent- needed in very small amounts
- produces long lasting effects in the cells they target
- regulates metabolic processes (maintains homeostasis)
- are regulated by negative feed-back mechanisms (negative = decreased release) (positive feedback = increased release)
- may be: steroidal or non-steroidal
Distinguish between a steroidal and non-steroidal hormone, in terms of composition and action
Steroidal: (produced from cholesterol = fat soluble)
passes easily through target cell membrane.
Non-Steroidal: (water soluble). Requires a receptor on the target cell membrane to allow the hormone to enter the cell. –>(activates a 2nd messenger that activates a cell.)
Endocrine Glands
HA(PPPP)(TTT)O
- Hypothalamus
- Adrenals
- Pituitary (hypophysis)
- Pineal gland
- Parathyroids
- Pancreas
- Thyroid
- Thymus
- Testes
- Ovaries
Hypothalamus
Secretes “releasing hormones”/ “inhibitory”, that target the anterior pituitary gland. (Most hormones begin with the hypothalamus)
Anterior pituitary gland secretes what 7 hormones?
Secretes 7 different hormones:
- Human Growth Hormone (HGH)
- Thyroid Stimulating Hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Prolactin (PRL)
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
- Melanocyte Stimulating Hormone (MSH) –>melanin
Hormone Secreted: HGH
a. Target organ of the hormone
b. Effect of each hormone
a. targets: bone, muscle, and adipose tissue
b. controls growth of body
Somatotropin:
From pituitary gland, Pituitary GH
Somatomedin:
From the liver. Directly responsible for growth of muscles and bones
Hormone Secreted: TSH
a. Target organ of the hormone
b. Effect of each hormone
a. thyroid gland
b. controls secretion of hormones by the thyroid gland
Hormone Secreted: ACTH
a. Target organ of the hormone
b. Effect of each hormone
a. Outer portion of the adrenal gland (cortex)
b. controls the secretion of hormones by adrenal cortex
Hormone Secreted: PRL
a. Target organ of the hormone
b. Effect of each hormone
a. mammary glands
b. stimulates production of milk
Hormone Secreted: FSH
a. Target organ of the hormone
b. Effect of each hormone
a. it’s a gonadotropin (stimulates activity of gonads), which targets ovaries and testes
b.
Females: FSH stimulates maturation of an ovarian follicle and ovum (formation of endometrium)
Males: FSH stimulates maturation of sperm in testes
Hormone Secreted: LH
a. Target organ of the hormone
b. Effect of each hormone
a. it’s a gonadotropin, which targets ovaries and testes
b.
Females: LH causes ovulation
Males: LH causes secretion of testosterone
Pregnancy hormone
progesterone
“master” of the anterior pituitary gland
Hypothalamus
Define gonadotropin and the 2 gonadotropins that are secreted by the anterior pituitary gland:
FSH and LH
Explain how the posterior pituitary gland does NOT produce hormones, but DOES secrete them:
Doesn’t produce hormones because the hypothalamus does this, but DOES store them until stimulated to release them.
Releasing Hormones (inhibitory) secreted by Hypothalamus that target the Anterior Pituitary Gland:
- HGH
- TSH
- ACTH
- PRL
- FSH
- LH
- MSH
Catecholamines
epinephrine and norepinephrine
Describe how calcium levels are maintained in the blood
Calcitonin and PTH
Calcitonin: Decreases blood calcium levels
(stimulates OSTEOBLASTS) and targets DISTAL convulated tubules
Parathyroid Hormone PTH:
Increases blood calcium
(activates OSTEOCLASTS) bones cells targets PROXIMAL convulated tubules
What 2 hormones work together to regulate water and electrolyte levels in blood thus regulating blood pressure
ADH and Aldosterone
causes DCT to reabsorb water back into bloodstream, therefore controls water balance and increases BP
Where is ADH made
made in Supraoptic nuclei of Hypothalamus
-Targets Collecting Ducts of Kidneys
Where is Oxytocin (OT) made?
made in Paraventricular nuclei
Describe how glucose levels are maintained in the blood
Pancreas:
functions as a mixed gland (endo and exocrine-> digestion)
-Endocrine: Islets of Langerhans produces Insulin and Glucagon.
Insulin: (eating) produced by BETA cells, DECREASES blood glucose levels
Glucagon: (fasting) produced by ALPHA cells, INCREASES glucose levels
Why does the Thymus gland decrease as we age?
the immune system produces most of the T cells during childhood and requires very few after puberty.
this gland produces the hormone, Thymosin which affects maturation of lymphocytes (T-cells)
which gland (hormone) whose production is stimulated by sunlight?
Pineal Gland secretes melatonin, which regulates sleep cycles
Define Gonads
they produce gametes: germ cell that unites w/opp sex to produce a zygote
Function of LH
Secreted by: anterior pituitary
Targets:
Males-> interstitial cells in testes -> testosterone secretion
Females -> mature ovarian follicle -> ovulation
Function of FSH
Targets:
Males-> tubules of testes - sperm production
Females-> ovarian follicle - follicle/ovum maturation
Adrenal Cortex (outer portion of adrenal gland, on top of kidney) Produces steroid hormones when stimulated by ACTH
- -Top:
Zona Glomerulosa : Aldosterone - increases BP - also a mineralcorticoid - Zona Fasciculata (biggest zone): Cortisol - regulates metabolism along w/ T3 and T4 - also a Glucorticoid
3.-bottom zone:
Zona Reticularis: supplemental sex hormones (estrogens and adrogens) that target secondary sex hormones
Adrenal medulla is the next layer down
Pituitary Dwarfism
slow bone growth and closing of epiphyseal plates before normal height is reached - they are short in stature
Hyposecretion of GH during growth years
Pituitary Giantism
abnormal increase in length of bones
Hypersecretion of GH during growth years
Acromegaly
Appositional growth
hands, feet, cheeks, jaw, thicken
Hypersecretion of GH during adulthood
Diabetes Mellitus : Type 1
- 10%
- Idiopathic
- Patients <20 years
- absolute insulin deficiency
- autoimmune disorder (b cells are destroyed/don’t make insulin like they are suppose to)
- Hyperglycemia
- Ketoacidosis (low pH)
complications of diabetes
Atherosclerosis, CV disease, gangrene, blindness, retinal vascular disease, renal failure
Diabetes Mellitus: Type ll
90%
- patients >40 years
- overweight
- hypertension
Thyroxine (T4) and
Triiodothyronine (T3)
9/1 ratio
90% T4-> Storage form
T3 is biologically active form
- they increase basal metabolic rate by stimulating cellular oxygen used to produce ATP
- Regulate metabolism
Chief Cell
secretes parathyroid hormone from the parathyroid gland
