Exam 3 Flashcards
control system which uses chemical messengers called hormones
endocrine system
- Consists of widely scattered endocrine glands
- Regulates important processes in the body
endocrine system
major processes regulated by endocrine system
- Reproduction
- Growth and development
- Mobilization of body defenses
- Maintenance of electrolytes and water balance
- Cellular metabolism and energy balance
- ________- leptin
o Regulates food intake
o Suppresses appetite
Adipose tissue
- _______- gastrin, secretin
o Stimulates movements and secretions of digestive system
Digestive system
- ______- erythropoietin
o Stimulates red blood cell production
kidneys
- _________– ANP
o Decreases sodium reabsorption by kidneys and lowers BP and BV
Heart
____-vitamin D
skin, liver, kidney
- ________- hCG, estrogen, progesterone, prostaglandins
o hCG- hormone of pregnancy
o Prostaglandins- labor contraction
placenta
carried by blood, act on distant target cells
- Circulating hormones (long distance hormones) -
- are ductless
- secrete into interstitial fluid
endocrine glands
do not circulate in blood
- Local Horemons
target neighboring cells
- prostaglandins
- interleukin-2
paracrines
target the same cells that made the hormones
- interleukin- 2
autocrines
chemical classes of hormones
- Lipid soluble
- Water soluble
- Eicosanoids
steroids and thyroid hormone
Lipid-soluble
amines (modified single amino acid) , peptides (short chains of amino acids), and proteins (large molecules made of amino acids)
water-soluble
(usually local hormones) - made from arachidonic acid (fatty acid) , released from cell membranes
a. Ex. Prostaglandins, leukotrienes (local inflammation)
Eicosanoids
Ovaries (estrogen)
Testes (testosterone)
Adrenal cortex
steroids
insulin and growth hormone
proteins
use Direct Gene Activation- can diffuse across cell membranes
- Lipid- soluble hormones
use Second Messenger Activation- can not cross cell membranes
- Water-soluble hormone
Direct Gene Activation by Lipid-Soluble hormones:
- Hormone diffuses through plasma membrane
- Binds to receptor inside the target cell
- Transcription of a specific gene
- New protein is made by cell (translation)
Second Messenger Activation by Water-Soluble hormones:
- Hormone (1st messenger) binds to receptor on target cell surface
- This causes a 2nd messenger to be made inside the cell
a. Example: cyclic AMP
- 2nd messenger activates protein kinase
- Protein kinase activates a protein
responds to an imbalance in the body fluid
o Ex. Parathyroid gland secretes parathyroid hormone (PTH)
o Hypothalamus secretes ADH
- Humoral stimulus-
responds to the nervous system
o Ex. CNS stimulates Epinephrine and norepinephrine
- Neural stimulus-
responds to a hormone from another endocrine gland
o Ex. Pituitary gland makes TSH -targets thyroid gland
o Pituitary gland makes ACTH – targets adrenal gland
- Hormonal stimulus (most common) -
makes water-soluble hormones
hypothalamus and pituitary gland
bundle of axons in the central nervous system
tract
o The hypothalamic-hypophyseal tract is the neural connection between hypothalamus and posterior pituitary
- Neurohypophysis- posterior pituitary and infundibulum
o The hypophyseal portal vein is the vascular connection between the hypothalamus and anterior pituitary
- Adenohypophysis- anterior pituitary
The hypothalamus makes 2 hormones that are sent by the hypothalamic-hypophyseal tract to the posterior pituitary:
ADH and Oxytocin
o Effect: Increases facultative water reabsorption, kidenys produce small volume of concentrated urine.
o Stimulus: humoral stimulus (dehydration) osmolarity goes up
ADH
o Effect: Stimulates labor contractions, milk is released from mammary glands
oxytocin
Then these 2 hormones are secreted into the blood from the posterior pituitary
oxytocin and ADH
The hypothalamus makes hormones that are transported by the hypophyseal portal veins to the anterior pituitary:
- releasing hormones (RH)
- inhibiting hormones (IH)
o Effect: hormonally stimulate the anterior pituitary to secrete a specific hormone
releasing hormone (RH)
o Effect: hormonally inhibits the anterior pituitary from secreting a specific hormone
inhibiting hormone (IH)
Water-soluble hormones are secreted from the anterior pituitary in response to ____or ____secreted from the hypothalamus:
RH and IH
effect:
stimulates growth, development of body cells
Growth Hormone (GH)
effect:
stimulates the thyroid gland to secrete the thyroid hormone
thyroid stimulating hormone (TSH)
stimulates the adrenal cortex to secrete many steroids
ACTH
stimulates production of gametes (egg, sperm)
FSH- targets ovaries, testis
stimulates production of sex hormones
LH- targets ovaries, testis
stimulates mammary glands to produce and store breastmilk
prolactin
a. Largest major endocrine gland
b. Stores 2-3 months of thyroglobulin- storage form of thyroid hormone
c. TH is the body’s main metabolic hormone
thyroid gland
The thyroid gland consists of 2 different kins of hormone-secreting cells:
- Follicular cells-make, store, and secrete TH (lipid-soluble hormone)
o Stimulus: hormonal stimulus by TSH
- Parafollicular cells- make calcitonin (water soluble)
Thyroid hormone is a mixture of T3 and T4:
- T3 (triiodothyronine) has 3 iodines attached to cross-linked tyrosine
- T4 (thyroxine) has 4 iodines attached to cross-linked tyrosines
· Increase basal metabolic rate (BMR)- rate of energy use during rest
· Maintains BP
· Regulates normal growth and development
effects of TH (t3 and t4)
· Secreted by parafollicular cells of the thyroid glands
o Effect: lowers blood Ca+2
o Stimulus: humoral stimulus (too much calcium in blood)
- not called thyroid hormone even though secreted by the thyroid gland
Calcitonin is a water-soluble hormone
- secretes water-soluble parathyroid hormone (PTH)
o Effect: raises blood calcium
o Stimulus: Humoral stimulus (too little calcium in blood) (low blood calcium)
parathyroid gland
respond to stressors- Ex: being sick (physical stress) (emotional stress)
adrenal glands
- secretes steroids- helps with long term stressors
o Stimulus: hormonal stimulus by ACTH(AC=adrenal cortex)
Adrenal cortext
secretes water-soluble hormones- helps with short term stressors
o Stimulus: Neural stimulus by sympathetic
Adrenal medulla
secretes mineralocorticoids (regulate mineral and water balance), mainly Aldosterone (most abundant).
§ Effects: increase in sodium reabsorption, increase blood volume increase blood pressure
- Zona glomerulosa
secrets glucocorticoids (regulates energy balance), mainly cortisol.
§ Effects: Regulates blood glucose (sugar), high levels suppress immune system
- Zona fasciculata
secretes gonadocorticoids (affect gonads (ovaries, testes), mainly weak androgens.
§ Effects: stimulates onset of puberty
Zona reticularis
adrenal medulla secretes was and what are the effects
- Epinephrine
o Effects: blood glucose increase, heart rate increases, airways dilate
- Norepinephrine
o Effects: vasoconstriction, raises blood pressure
(exocrine and endocrine gland):
o 99% of cells are acinar cells- produce digestive enzymes (exocrine)
o 1% of cells make water-soluble hormones that regulate blood glucose (endocrine):
- Alpha Cella
-Beta Cells
pancreas
make glucagon
· Effects: raises blood glucose
Alpha cells (a)
make insulin
- effects: lowers blood glucose
beta cells (b)
secrete estrogen and progesterone (steroids)
ovaries
secrete testosterone (steroid)
testes