Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NE Exam 3 > Histology Of Endocrine Organs > Flashcards

Histology Of Endocrine Organs Flashcards

1
Q

What are humoral stimuli?

A

Release of hormone controlled by monitoring levels of ions and nutrients in blood and body fluids
Ex. Monitoring Ca levels - release of PTH stimulated by low serum Ca)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are neuronal stimuli?

A

Release of hormone stimulated by nerve signals

Ex. Release of epinephrine from adrenal gland in response to a signal from sympathetic nerve fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are hormonal stimuli?

A

Release of hormone caused by a hormone secreted into bloodstream by another endocrine organ or cell
Ex. Release of thyroid hormone stimulated by release of TSH from the pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the organization of endocrine glands

A

Endocrine cells are arranged in cords, clusters or follicles and some are found as isolated individual cells
Are derived from epithelium and are epithelioid in nature (lack a free luminal surface)
Well vascularized with capillaries lined with fenestrated endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the direct targets of the hypothalamus?

A

Anterior pituitary gland by secreting releasing or inhibiting factors
Kidney and uterus by releasing ADH and oxytocin in the posterior pituitary
Adrenal medulla via sympathetic innervation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the indirect targets of the hypothalamus?

A

Hypothalamus releases hormones (collectively referred to as the trophic hormones) that stimulate or inhibit the release of hormones from the anterior pituitary
Indirectly influences other endocrine organs by stimulating secretion of hormones by the anterior pituitary gland
Ex include hypothalamic hormones that stimulate release of TSH, somatotropin, ACTH, FSH and LH, prolactin and MSH from anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the embryological origin for the pituitary gland?

A

Anterior pituitary - from an ectoderm diverticulum that forms a vesicle called Rathke’s pouch and this ouch translocates towards and joins the developing infundibulum of the diencephalon
Posterior pituitary and infundibular stalk - from infundibular diverticulum of the diencephalon of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the anterior pituitary gland composed of?

A

Glandular epithelial cells controlled by neurohormones released from hypothalamus
Includes the pars distalis (anterior most lobe of the pituitary), pars intermedia (intermediate lobe) and pars tuberalis (wraps around infundibular stalk)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the posterior pituitary composed of?

A

Axons from hypothalamus and support cells
Axons carry ADH and oxytocin for storage and release in posterior pituitary
Includes pars nervosa (posterior lobe), median eminence (base of the hypothalamus), and infundibular stalk (thin portion extending down from the eminence)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the major cell types in the anterior pituitary gland?

A

Somatotropin cells, thyrotropic cells, corticotropic cells, gonadotropic cells and mammotropic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do somatotropin cells secrete?

A

GH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do thyrotropic cells secrete?

A

TSH regulating thyroid gland secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do corticotropic cells secrete?

A

ACTH and melanocyte stimulating hormone (MSH)
ACTH stimulates adrenal cortex to secrete stress related hormones and mediate metabolism
MSH stimulates melanocytes to produce melanin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do gonadotropic cells secrete?

A

FSH and LH that act on the gonads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do mammotropic cells secrete?

A

Prolactin which stimulates milk production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What cells comprise the pars distalis of the anterior pituitary?

A

Acidphils, basophils, chromophores (unknown function) and sinusoidal (fenestrated) capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which cells are acidphils?

A

Somatotrophs (GH) and mammotrophs (prolactin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What cell types are basophils?

A

Corticotrophs (ACTH), thyrotrophs (TSH) and gonadotrophs (LH and FSH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the pars nervosa

A

Continuous with median eminence of the hypothalamus via infundibular stalk
Does not manufacture hormones rather stores and releases them from axon terminals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the pars nervosa consist of?

A

Hypothalamus unmyelinated axons (contain Herring bodies which are expanded axonal terminals storing ADH and oxytocin)
Pituicytes (glia-like) supporting the nerve fibers
Fenestrated capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of ADH?

A

Targets the kidney and regulates Na and water retention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the role of oxytocin?

A

Targets uterine smooth muscle and stimulates lactation

Induces brith and may be involved in sexual arousal and pair and social bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the hypothalamic portal system

A

Responsible for delivery of hypothalamic trophic hormones to the anterior pituitary
Hypothalamic neurons secrete hormones and the capillary plexus supplying it takes up the released hormones
Venous capillaries carrying the hormones then drain into the hypothalamic portal veins leaving the hypothalamus
Hypothalamic portal wins enter ant pit and break up into capillary plexus where they signal ant pit cells
Ant pit releases hormones into the same surrounding capillary plexus that then drains into the pituitary veins and enters the systemic circulation

24
Q

Describe the pineal gland

A

Out pocketing of diencephalon’s roof of 3rd ventricle
Flattened and cone shaped covered with pia mater
Role in growth, development and circadian rhythms
Synthesizes melatonin and serotonin

25
Q

What does the pineal gland consist of?

A

Pinealocytes and neuroglia
Calcified granular material (brain sand) - ca phosphate crystals located in the intercellular spaces that show up beginning early childhood; important radiogenic marker (for midline brain); secreted by pinealocytes

26
Q

Describe the microscopic anatomy of the thyroid gland

A

Characterized by structures called follicles consisting of a layer of follicular cells (simple cuboidal to columnar epithelium) surrounding a fluid called colloid
Colloid contains thyroglobulin (a storage form of T3 and T4)

27
Q

What is the only gland to store a hormone outside of the cell?

A

Thyroid gland

28
Q

Thyroid hormones control what?

A

Basal metabolism, O2 usage, body temp, etc

29
Q

Describe the synthesis and turnover of thyroid hormones

A

Generated and stored extracellularly as thyroglobulin
Thyroglobulin synthesized in rER, glycosylated in golgi and secreted by exocytosis into the lumen of follicle (colloid)
Thyroglobulin is iodinated at the apical surface forming T3 and T4
TSH stimulates internalization of thyroglobulin via endocytosis where it is degraded freeing T3 and T4
T3 and T4 are released from the basal surface of the follicle cells into the circulation

30
Q

What are parafollicular C cells?

A

Lie just outside the follicles
Secrete calcitonin when blood levels of Ca are high
Lower circulating Ca levels by stimulating secretion by kidneys, decreasing the Ca releasing activity of osteoclasts and increasing osteogenesis by osteoblasts

31
Q

What is Graves’ disease?

A

Abnormal Abs stimulating TSH receptors causing over secretion of T3 and T4
Sx: elevated metabolism, sweating, rapid HR, weight loss, eye balls may protrude
May need thyroidectomy or anti-thyroid drugs
More common in women

32
Q

What is hypothyroidism?

A

Insufficient T3 and T4 production
Often an autoimmune disease causing follicle cell death
Sx: low metabolic rate, weight gain, lethargy, chilliness, edema, mental sluggishness
Treated with synthetic T3 and T4

33
Q

What are goiters?

A

Thyroid enlargement most commonly due to iodine deficiency

Follicle cells keep producing thyroglobulin but cannot iodinate it to make TH

34
Q

What are the parathyroid glands?

A

Small ovoid glands (usually two pairs) lying on the posterior surface of the thyroid gland that release PTH
Major importance in regulating serum Ca and phosphate levels
Blood supply to the parathyroid glands is similar to the thyroid

35
Q

What cells are within the parathyroid glands?

A

Chief (principle) cells and oxyphil cells (function unknown but increase with age)

36
Q

What are chief (principle) cells?

A

Located in the parathyroid glands and release PTH
Secretion occurs when the blood concentrations of Ca falls below the normal range of 9.5-10.5 mg/dL
Secretion stops when the level of Ca returns to normal

37
Q

Describe the Ca regulation that occurs by PTH

A

PTH released from chief/principle cells when blood levels drop below 9.5mg/dL
Stimulates osteoclasts to resorb bone and release its Ca stores, increase Ca retention by the kidneys, stimulates kidney to convert an inactive form of vitamin D to calcitriol (active form) which then increases Ca absorption by the intestines
Blood Ca levels increase and then inhibit further PTH release

38
Q

Describe the adrenal cortex

A

Distinctive yellow color due to lipids in its cells

Divided into structurally and functionally 3 zones including the zona glomerulosa, zona fasciculata, zona reticularis

39
Q

Describe the zona glomerulosa

A

Mineralocorticoids
Influence Na and K levels (salt)
Aldosterone is released from this layer

40
Q

What is the function of aldosterone?

A

Targets kidney function
Mostly secreted in response to low BP or blood volume
Controlled by renin-angiotensin system

41
Q

Describe the zona fasciculata

A

Glucocorticoids like cortisol
Influence glucose metabolism and immune system
Released under the control of ACTH from the anterior pituitary

42
Q

What is the function of cortisol?

A

Deals with stress and mediates glucose metabolism
Serves as negative feedback mechanism to the immune system (anti-inflammatory action)
Released primarily by the zona fasciculata but also the zona reticularis

43
Q

Describe the zona reticularis

A

Androgens

Influence secondary sex characteristics

44
Q

Describe the adrenal medulla

A

Forms the inner core of each adrenal gland
Primarily consists of clusters of large spherical cells called chromaffin cells (target of presynaptic sympathetic neurons)

45
Q

Describe what occurs when the adrenal medulla is stimulated by the sympathetic NS

A

When stimulated by the sympathetic NS one population of cells primarily secretes the hormone epinephrine (adrenaline) and a second population primarily secretes the hormone NE (noradrenaline)
These hormones work with the sympathetic NS to prepare the body for an emergency or fight or flight situation

46
Q

What is Addison’s disease?

A

Hyposecretory disorder usually in both glucocorticoids and mineralocorticoids
Blood glucose and Na levels drop and there is severe dehydration and low BP along with fatigue and loss of appetite
Causes include autoimmune disease or due to an inherited metabolic disease leading to deficiencies in hormone producing enzymes

47
Q

What is Cushing’s syndrome?

A

Due to hyper secretion of glucocorticoids because of either an ACTH secreting pituitary tumor or a tumor in the adrenal cortex
Characterized by high serum glucose levels, protein loss in muscles, muscle weakness, depressed immune system and lethargy

48
Q

What are some sx of Cushing’s syndrome?

A

Swollen face, fat redistribution (buffalo hump and moon face), high glucose levels, weight gain, sweating, thinning skin, muscle weakness, lethargy, depression of immune and inflammatory responses

49
Q

Describe the exocrine portion of the pancreas

A

Makes up most of the gland
Aids in digestion
Exocrine cells are organized in structures called pancreatic acini

50
Q

Describe the endocrine portion of the pancreas

A

Endocrine cells are organized into clusters called pancreatic islets or islets of Langerhans
The islets are scattered amongst the exocrine cells

51
Q

What cells make up the pancreas?

A

Alpha, beta, delta and F-cells

52
Q

What are alpha cells?

A

Secrete glucagon when blood glucose levels drop

Stimulates release of glucose from liver glycogen stores

53
Q

What are beta cells?

A

Secrete insulin when blood glucose levels are elevated

Promotes glycogen storage in the liver and entry into cells

54
Q

What are delta cells?

A

Secrete somatostatin slowing the release of insulin and glucagon thereby controlling the rate of nutrient entry into the bloodstream and cells
Regulates several digestive related hormones
Stimulated by high levels of nutrients in bloodstream

55
Q

What are F cells?

A

Secrete pancreatic polypeptide that inhibits the release of somatostatin
Has a role in appetite regulation

56
Q

Describe pancreatic blood supply

A

The pancreas has two arterial capillary flows: one entering the islets and the other supplying the pancreatic acinar cells hence providing arterial blood separately to the endocrine and exocrine portion of the gland
Venous capillaries draining the islets flow over the acinar cells to apply local action of islet hormones more directly to the exocrine cells of the pancreas

NE Exam 3 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions