Endocrine Histology and Embryology Flashcards Preview

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Flashcards in Endocrine Histology and Embryology Deck (82)
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1
Q

What is the primary function of the endocrine system

A

aid in establishment and maintenance of homeostasis

2
Q

What is the main difference between endocine and exocrine glands

A

endocrine glands release their products directly into the bloodstream (ductless Glands), Exocrine glands release their products through ducts to an external environment (duct glands)

3
Q

What are endocrine cells called

A

??

4
Q

What is the chemical signal of the endocrine system

A

hormones

5
Q

what determines cell response with the endocrine system

A

??

6
Q

How fast is the speed of onset of the endocrine system

A

??

7
Q

What is the duration of action of the endocrine system

A

??

8
Q

What are the 9 main endocrine glands of the endocrine system

A
Pituitary (anterior and posterior)
Hypothalamus
Pineal
Thyroid
Parathyroid
Thymus
Adrenal glands
pancreatic islets
ovaries/testes
9
Q

What is a hormone

A

a long distance chemical mediator produced by an endocrine gland, released into the bloodstream and transported to its target cells where it interacts with specific cells and affects cell function

10
Q

What are the three main types of hormones

A

protein/peptide hormones
steroids (cholesterol based)
Eicosanoids

11
Q

Where is the hypothalamus located, what is it made of, and what does it secrete

A

it is located at the base of the brian
it is made of brain tissue
It secretes ADH (anti-diuretic hormone) and Oxytocin
as well as hypothalamic-releasing and inhibiting hormones

12
Q

What part of the brain in development develops into the hypothalamus, pituitary, and pineal gland

A

the Diencephalon

13
Q

What cells of the hypothalamus secrete ADH and Oxytocin, and what happens to them once they are secreted

A

the neurosecretory cells secrete ADH and Oxytocin, once they are secreted they go to the posterior pituitary for storage, until they are released into the bloodstream

14
Q

What is another name for the hypophysis

A

pituitary gland

15
Q

where is the pituitary gland found

A

at the base of the hypothalamus

16
Q

what are the two parts of the pituitary gland

A

the anterior and posterior pituitary

17
Q

what tissue is the anterior pituitary made of

A

glandular epithelium

18
Q

what tissue is the posterior pituitary made of

A

neural tissue

19
Q

What are the steps in development of the pituitary gland

A
  1. infundibulum extends from the diencephalon toward the stomodeum
  2. Rathke’s pouch evaginates up from the stomodeum up towards the infundibulum
  3. Rathke’s pouch loses connection with the stomodeum, and lies anteriorly to the infundibulum
  4. Rathke’s pouch develops into adenhypophysis
  5. infundibulum develops into neurohypophysis
20
Q

What are the three parts of the adenohypophysis

A
anterior lobe (pars distalis)
pars tuberalis (surrounds infundibulum)
Pars intermedia (cells that form between ant. and post. pituitary)
21
Q

What are the three parts of the neurohypophysis

A

pars nervosa (posterior lobe)
pituitary stalk
infundibuluar recess

22
Q

what is found in the pars nervosa

A

lots of non-myelinated axons and nerve endings

23
Q

what are herring bodies

A

where the non-myelinated axons in the pars nervosa terminate

24
Q

what is found in the infundibulum

A

nerve tracts from the hypothalamus to the pars nervosa

25
Q

Where does the hypothalamus release its hormones

A

into the interstitial fluid of the median eminence

26
Q

what kind of capillaries are found in the median eminence of the pituitary gland

A

fenestrated

27
Q

what is the blood vessel system like in the pituitary gland

A

it is a portal system
there is a superior hypophyseal artery which enters the pituitary at the median eminence, where it picks up the hypothalamic hormones and takes them to the anterior pituitary through portal vessels.
there is an inferior hypophyseal artery which enters the posteior pituitary, picks up those hormones.
all the vessels leave as hypophyseal veins

28
Q

which neurons of the hypothalamus send their hormones to the anterior pituitary, via the superior hypophyseal artery, after releasing them to the median eminence

A

neurosecretory neurons

29
Q

which neurons of the hypothalamus send their hormones to the posterior pituitary

A

the supraoptic nuclei, and the paraventricular nuclei

30
Q

What are the three ways in which the hypothalamus regulates the body

A

direct control by nervous system
direct release of hormones
indirect release of hormones

31
Q

what body tissues does the hypothalamus directly control by the nervous system

A

the adrenal medulla, which secretes epinephrine and norepinephrine

32
Q

what body tissues does the hypothalamus directly control by hormones

A

the posterior pituitary, which secretes ADH (kidneys) and Oxytocin (prostate and uterine smooth muscle and mammary glands)

33
Q

what body tissues does the hypothalamus indirectly control through hormones

A

the anterior pituitary, the hypothalamus tells it to secrete its hormones

34
Q

what are the 7 hormones of the anterior pituitary

A
ACTH (adrenal corticotropic hormone)
TSH (thyroid stimulating hormone)
GH (growth hormone)
PRL (prolactin)
FSH (follicle stimulating hormone)
LH (leutinizing hormone)
MSH (melanocyte stimulating hormone)
35
Q

what is the action of ACTH

A

it causes the adrenal cortex to secrete glucocorticoids

36
Q

what is the action of TSH

A

it causes the thyroid to secrete thyroid hormones

37
Q

what is the action of GH

A

it causes the liver to secrete somatomedins, which affect bone, muscle and other tissues

38
Q

what is the action of PRL

A

it causes milk production from the mammary glands

39
Q

what is the action of FSH and LH

A

they cause the testes to produce inhibin and testosterone

they cause the ovaries to produce estrogen, progesterone, and inhibin

40
Q

what is the action of MSH

A

it goes to the melanocytes, action is uncertain

41
Q

what are the three disorders of GH

A

hyposecretion = pituitary dwarfism
hypersecretion before growth plates fuse = gigantism
hypersecretion after growth plates fuse = acromegaly

42
Q

What are the pharyngeal arches, pouches, and grooves derived from

A
arches = mesoderm
pouches = endoderm
grooves = ectoderm
43
Q

how many pairs of pharyngeal pouch pairs are there

A

4 (the 5th goes away)

44
Q

What develops from the 1st pharyngeal pouch

A

the tympanic cavity and pharyngotympanic tube

45
Q

what develops from the 2nd pharyngeal pouch

A

the palatine tonsil

46
Q

what develops from the 3rd pharyngeal pouch

A

the inferior parathyroid and they thymus

47
Q

what develops from the 4th pharyngeal pouch

A

the superior parathyroid and the ultimopharyngeal body

48
Q

what is the fate of the ultimopharyngeal body, and what does it secrete

A

it becomes the parafollicular cells (C-cells), and they secrete calcitonin

49
Q

what is the function of calcitonin

A

decreases blood calcium (opposition to the parathyroid hormone)

50
Q

What are the steps in the development of the thyroid gland

A
  1. thyroid primordium forms at the foramen cecum
  2. thyroid primordium moves down the thyroglossal duct
  3. thyroglossal duct dissapears
  4. two thyroid lobes connect via an isthmus
  5. thyroid descends to inferior of the cricoid cartilage
51
Q

what forms if the thyroglossal duct persists

A

a thyroglossal cyst or sinus

52
Q

What stimulates the thyroid to secrete its hormones, what are its hormones

A

thyroid stimulating hormone stimulates the thyroid to secrete Calcitonin, Triiodothyronine(T3), and thyroxin (T4)

53
Q

What are the teo types of cells in the thyroid

A

follicular cells

parafollicular cells

54
Q

what are the follicular cells and parafollicular cells like histologically

A

follicular cells are simple cuboidal epithelium

parafollicular cells are cuboidal

55
Q

What are the functions of T3 and T4

A

increase metabolism and assist in growth and development

56
Q

what is required for synthesis of T3 and T4

A

iodine

57
Q

what causes a goiter

A

too little iodine

58
Q

what are the symptoms of hypothyroidism (Myxedemia)

A
fatigue
weakness
weight gain
hair loss
depression
decreased libido
59
Q

what are the symptoms of hyperthyroidism (graves disease)

A
palpitations
nervousness
heat intolerance
insomnia
fatigue
fast heart rate
weight loss
bulging eyes
60
Q

what causes the secretion of cacitonin

A

high blood calcium levels

61
Q

what is caused when the thyroid fails to develop properly

A

cretinism

62
Q

what is the parathyroid gland

A

4 bean shaped glands embedded in the fascial sheath of the thyroid that secrete parathyroid hormone

63
Q

what is the function of parathyroid hormone

A

causes calcium to be moved into the blood from the bones (brakes down bones)

64
Q

What are the two divisions of the adrenal gland

A

the adrenal cortex (outside) and the adrenal medulla (inside)

65
Q

what are the three layers of the adrenal cortex from superficial to deep

A

glomerulosa
fasciculata
reticularis

66
Q

what does the adrenal medulla secrete

A

catecholectamines (epinephrine and norepineprhine)

67
Q

Where do the medulla and cortex originate from

A

medulla originates from the ectoderm

cortex originates from the mesoderm

68
Q

what are the steps in the development of the adrenal glands

A
  1. mesothelial cells penetrate underlying mesencyhme
  2. these cells differentiate into cortex
  3. mesothelial cells penetrate mesenchyme again
  4. these 2nd cells surround the first cells, and most of the first cells regress, except the reticularis zone
  5. neural crest cells invade the medial aspect of the cortex
  6. these neural crest cells invade and arrange in clumps and cords = adrenal medulla
69
Q

what are chromaffin cells

A

the neural crest cells that invade the primitive cortex and form the adrenal medulla

70
Q

what are the types of hormones (and specific hormones) secreted from the three layers of the adrenal cortex

A
Glomerulosa = mineralocorticoids (aldosterone)
Fasciculata = glucocorticoids (cortisol)
reticularis = sex hormones
71
Q

what is the function of aldosterone, and what causes it to be secreted

A

it causes sodium reabsorption into the blood in the kidneys, which causes water retention and assists in maintaining blood pressure.
blood pressure and electolyte balance regulate it by angiotensin 2

72
Q

what is the function of cortisol and what causes it to be secreted

A

it causes increase blood glucose, and decreases antibodies

it is regulated by ACTH (but caused by stress)

73
Q

what is the function of the sex hormones from the adrenal cortex and what regulates their secretion

A

they supplement the sex hormones from the gonads, and they are regulated by ACTH

74
Q

What is the disease with excessive ACTH

A

cushing syndrome

  • hyperglycemia and glucosuria
  • fat in the face, mid section, and above the shoulders
  • muscle tissue breakdown
75
Q

what is the disease with insufficient ACTH

A

addison disease

  • weight loss
  • fatigue
  • hypotension
  • skin darkening
76
Q

What are the two hormones secreted from the chromaffin cells of the adrenal medulla, what is their function, and what regulates them

A

epinephrine, norepinephrine (small amounts of dopamine)
they are important in fight or flight
they are regulated by the nervous system

77
Q

What is the pancreas

A

an organ with endocrine and exocrine function that lies below the stomach, and is attached to the duodenum, and is 90% acinar (exocrine) cells

78
Q

What are the steps in the development of the pancreas

A
  1. dorsal and ventral pancreatic buds grow off of the duodenum
  2. the ventral bud moves around the duodenum and joins with the dorsal bud
  3. the dorsal bud makes the head, body, and tail. the ventral bud makes the ucinate process and the main pancreatic duct
79
Q

What occurs when the ventral buds of the pancreas migrate in opposite directions around the duodenum

A

you have an annular pancreas, with which the duodenum will be constricted by the pancreas that has formed around it

80
Q

most of the pancrease if composed of ductal and exocrine glands, what is the remaining part of the pancreas made of

A

islets

81
Q

what are pancreatic islets? and why do they get most of the blood supply to the pancreas

A

the islets are where alpha, beta and delta cells are located. They get most of the blood supply to the pancreas because they are the endocrine portion of the pancreas (thus they secrete hormones into the blood)

82
Q

What do alpha, beta, and delta pancreatic cells produce

A

alpha cells produce glucagon
beta cells produce insulin
delta cells produce somatostatin