A&P Exam 4 Flashcards
(235 cards)
Pituitary Gland Gross Anatomy
- = pea on stalk (infundibulum)
- 2 Lobes (anterior and posterior)
Anterior Pituitary Lobe
Adenohypophysis
Makes / release 6 hormones
Posterior Pituitary Lobe
-Made of Neurohypothesis infundibulum
-Makes 2 hormones
Posterior Pituitary Hormone Acquisition and release steps
- Gets hormone from hypothalamus
- Cell bodies in nucleus synthesize hormones
- Transported down axon (hypothalamic-hypophyseal tract)
- When N. fires → H releases into posterior capillaries releasing hormone
5.Releases 2 Hormones= Oxytocin and Antidiuretic Hormone
Oxytocin
Produced :
-by hypothalamic paraventricular nuclei & released from posterior pituitary
Releases:
Positive feedback for uterus and cervix
Antidiuretic Hormone
Produced:
-Hypothalamic supraoptic nuclei, released post pituitary
Target:
-Renal CD (principal cells)
Effect:
-Reabsorbs H2O= less urine and increase blood volume
Release:
-Increases blood osmolality
-Drop in blood volume
What does too much antidiuretic hormone do?
Syndrome of Inappropriate ADH Secretion (SIADH):
-Retain Water
-Edema
-increased blood pressure
-Concentrated urine
-Increase in blood osmolality
Negative Feedback Loop:
-Stimulates hypothalamus to make ADH which is released by posterior pituitary
-Causes renal collecting ducts to reabsorb H2O
-Drops blood Osmolality
What does too little antidiuretic hormone do?
Diabetes Insipidus:
-Large amt of dilute urine, Thirst, and dehydration
Alcohol:
-Inhibits inhibits it
Posterior Pituitary Hormone Acquisition and Release
Hypothalamus controls it via hypophyseal portal system (blood vessels):
-Neurons release inhibiting and releasing hormones
-Picked up by primary capillary plexus to hypophyseal portal veins to secondary
capillary plexus to pituitary cells
*Sometimes called master endocrine gland
Growth Hormone
Target:
-Almost all cells
Effect:
-Mobilizes fat as fuel
-Increases size of cells (hypertrophy)
-Spares glucose increasing plasma glucose levels
-Stimulates protein synthesis
-Induce mitosis (long bone growth/ increase muscle mass)
Regulation:
-GHRH →increase Gh
-GHIH→decreases GH
-Highest at night
Too little Growth Hormone
Child→ pituitary dwarfism
4ft , but proportional
Tx= Growth hormone
Too Much Growth Hormone in Children
Gigantism:
-Typically from tumor
Example=
Robert Wadlow
Born 1919
4ft toddler
Died at 22
8ft 11in.
439 lbs.
Too Much Growth Hormone in Adults
-Overgrowth of membranous bone on Skull, face, hands
-Diabetes mellitus
Thyroid Stimulating Hormone
Target:
-Thyroid Gland
-Tropic hormone
Effects:
-Stimulates synthesis and release of Thyroid hormones
-Stimulates development of thyroid gland
Regulation:
-Increases by low thyroid levels and TRH
-Decreases by high Thyroid Hormone
Too Much:
-Hyperthyroidism
Too Little:
-Hypothyroidism
Adrenocorticotropic Hormone
Target:
-Adrenal cortex
Effects:
-Stimulation secretion of corticosteroid hormones
Regulation:
-Increased by stress, fever, drop in glucose levels (tend to be higher in morning)
-Decreases by high levels of corticosteroid hormone
Stops hypothalamus and anterior pituitary gland
Too Much:
-Cushing’s Disease
Too Little:
Rare
Gonadotropin Types
Follicle Stimulating Hormone and luteinizing Hormone
Gonadotropins
Target:
-Gonads
Effect:
-Regulate gonadal function
In Women=Oogenesis(egg production) &
Estrogen and progesterone production
Male=Spermatogenesis & Testes make testosterone
Regulation:
-Gonadal Releasing Hormone increases it
-Estrogen, progesterone, testosterone shuts it off
Too Much:
-Decrease libido
Too little:
-Fail to mature sexually
-Infertility
-amenorrhea
Prolactin
Target:
-Breast
Effects:
-Stimulate milk production
Regulation:
-Prolactin Inhibiting Hormone= dopamine
-Prolactin Releasing Hormone= suckling and estrogen
Too Much:
-Galactorrhea
Too Little:
-Lactation failure
Melanocyte Stimulating Hormone
Target:
-Melanocytes
Effect:
-Increases melanin production
-Sot significant in humans
6 Hormones released by anterior pituitary gland
1.Growth Hormone
2.Thyroid Stimulating Hormone
3. Adrenocortropic Hormone
4.Prolactin
5.Follicle Stimulating Hormone(gonadotropin)
6.Lutenizing Hormone
Hormone Produced by middle pituitary gland
Melanocyte Stimulating Hormone
Hormones produced by thyroid gland
1.Thyroid Hormone
2.Calcitonin
Thyroid Anatomy
- 2 lobes and isthmus
- Largest purely endocrine gland
- Has good blood supply
What does the Thyroid gland arise from in embryology?
endoderm