Endocrine Glands Flashcards
1
Q
What is Endocrine Secretion
A
Endocrine glands lack ducts-
Their secretory products (hormones) generally pass into blood or lymphatic circulation.
2
Q
Define Paracrine Secretion
A
Secretory products (hormones) are secreted directly into the intercellular space (interstitial fluid or short loops of blood vessels) to elicit a local effect on adjacent cells.
3
Q
Define Autocrine Secretion
A
Hormones that are secreted into the vascular system and eventually enter the tissue fluids & depending on specificity of hormones can alter the activities of one or more organ
4
Q
What are Target Organs
A
Organs that respond to a specific hormone
5
Q
Hormones can be classified into 3 general categories according to their chemical structure…
Name 3 categories
A
- AA Polymers ( Polypeptides, Proteins, Glycoproteins)
- Cholesterol derivatives (Sterols &Steroids)
- Tyrosine Derivatives (Thyroid hormones & catecholamines)
6
Q
T or F
In autocrine secretion, cells may produce molecules that act themselves or on cells off the same type.
A
T
7
Q
Give an example of an autocrine Secretion cell that produces molecules that act on themselves
A
IGF- Insulin-growth factor produced by several cells that my act on cells that produce it.
8
Q
Pituitary Gland is also know as
A
Hypophysis
9
Q
Pituitary Gland dimensions
A
.5 g in adults and demotions of 10x13x6mm
10
Q
Where is Pituitary Gland found
A
Lies below the brain in a small cavity on the sphenoid bone, the Sella Turcica (depression in the sphenoid bone)
11
Q
Pituitary Gland consists of 2 glands
Name them
A
- Anterior (Adenohypophysis)
2. Posterior (Neurohypophysis)
12
Q
Neurohypophysis retains many histologic features of brain tissue and consist of a large part of ________ & the small _________
A
Pars nervosa & small infundibulum (stalk is the top of a slide, Pars is the bottom portion)
13
Q
Define Pars Nervosa
A
Contains the endings of neurosecretory neurons, capillaries & pituicytes
14
Q
Pituitary gland forms form 2 separate embryonic structures
Name these structures
A
- Hypophyseal pouch or Rathke pouch is the future Anterior Pituitary - grows form the roof of the pharynx.
- Neurohypophyseal bud the future Posterior Pituitary forms from the diencephalon
15
Q
Adenohypophysis derives form the ______ , has 3 parts name parts
A
Oral ectoderm
- Large = Pars Distalis
- Anterior Lobe = pars tuberalis (wraps around the infundibulum)
- Thin = pars intermedia adjacent to the Posterior pars nervosa
16
Q
Pituitary gland is connected to what
A
Hypothalamus at the base of the brain
17
Q
Define hypothalamic-hypophyseal tract
A
System of blood vessels in the microcirculation at the base of the brain connecting the hypothalamus with the anterior pituitary.
Function: quickly transport & exchange hormones between the hypothalamus & Anterior Pituitary gland
18
Q
Superior Arteries divide into what
A
Primary Plexus of fenestrated capillaries that irrigate the Salk & medial eminence.
19
Q
Define fenestrations
A
Pores that will allow large molecules through
Found in= where their is extensive molecular exchange with the blood such as small intestine, endocrine glands & kidneys.
20
Q
Hypothalamus specialized neuron clusters called ________ cells produce what type of hormone or hormones
A
Neurosecretory Cells
Antidiuretic Hormone (ADH)
Oxytocin (OXT)
Transported to the pituitary stored for later
21
Q
ADH and Oxytocin are synthesized by large neurons in the ______ and the ______
A
Supraoptic nuclei
Paraventricular nuclei
22
Q
Blood supply derives from 2 groups of vessels, coming off the _______ ________ _______ and drained by the ______ ______
A
Internal Carotid Artery
Hypophyseal vein
23
Q
Superior Hypophyseal arteries supply the ____ ____ and the _____ _____
A
Median eminence
Infundibular stalk
24
Q
Inferior hypophyseal arteries provide blood mainly _______
A
Neurohypophysis
25
Superior arteries divide into _____ _____ of fenestrated capillaries that irrigate the ______ & ______ ______.
Primary Plexus
Stalk
Median eminence
26
Adenohypophysis is also known as _______
| Has 3 parts
Anterior Pituitary Gland
Large Pars distalis
Pars tuberalis surrounding the infundibulum
This pars intermedia
27
Endocrine cells of the anterior pituitary are called ______ ______ ______ based on their staining properties
Acidophils
Basophils
Chromophobes
28
Pars Distalis is part of what and what is its main component
Anterior pituitary
Accounts of 75 % of Adenohypophysis
Has thin fibrous capsule
Main component: cords of well stained endocrine cells interspersed with fenestrated capillaries & supportive reticular tissue
29
Pars Distalis - name different staining affinities
Chromophils- secretory cells in which hormones are stored in cytoplasmic granules.
Chromophobes
30
Chromophils are also known as what
Basophils
Acidophils
Based on their affinities for basic & acidic dyes
31
Acidophils secrete either _______ _______ or _________ and are called ________ & ________.
Growth Hormone (somatotropin)
Prolactin
Are called - somatotrophs & lactotrophs
32
Basophilic cells are the _____, ______ & _______ with target cells in the _______ cortex, ______, &——— gland.
```
Corticotrophs
Gonadotrophs
Thyrotrophs
Adrenal
Gonads
Thyroid
```
33
Gonadotrophs secrete 2 different glycoproteins ?
1. Follicle-Stimulationg hormone (FSH)
| 2. Leutenizing Hormone (LH) or ICSH in Men (interstitial cell-stimulating hormone)
34
Main protein synthesized in Corticotrophs is
POMC= pro-opoimelanocortin which is cleaved posttranslatinally into the polypeptide hormones ACTH-adrenocortical tropic Hormone and B-lipoprotein (B-LPH)
35
Hormones produced by the Pars Distalis regulate almost all other endocrine glands...name
Ovarian function
Sperm production
Milk production
Metabolism of muscle, bone, adipose tissue
36
Define Pars Tuberalis & most of its cells are ______
Smaller funnel shaped region surrounding the infundibulum of the neurohypophysis.
Part of the anterior lobe of the APG and wraps the pituitary stalk in a Highly Vascularized sheath.
Most of cells are Gonadotrophs
37
What are the major cell types of Anterior Pituitary & major function
1. Somatotrophs= stimulates Growth in Epiphyseal plated of long bones via insulin like growth factors (IGF’s) produced in Liver
2. Lactotropsh or mammotrophs= Milk secretion
3. Gonadotrophs = FSH promotes ovarian follicle development & estrogen secretion
4. Thyrotrophs= Stimulates thyroid hormone synthesis, storage, liberation
5. Corticotrophs= stimulate secretion of adrenal cortex Hormone & regulation of lipid metabolism
38
Growth Hormone (GH) is responsible for what
```
Acts on all body tissues,
Cartilage
Bone
Muscle
Adipose tissue
```
39
Name 2 forms of Melanocytes-stimulating hormones (MSH)
Gamma- LPH & B-endorphin
40
Activities of the cells of Anterior Pituitary are controlled by what
Hypothalamic hormones
41
Another mechanism controlling activity fo AP cells is _____ _____ by hormones form the target organs
Negative feedback
42
Major hormones outside the feedback look or major target tissues are
Polypeptide ghrelin produced mainly in the stomach mucosa, also acts as a releasing hormone for Somatotropin & Oxytocin, released in the posterior pit during Brest feeding =increasing secretion of Prolactin
43
Posterior Pituitary is also know as
Neurohypophysis
44
PP gland is composed of what
Neural tissue containing 100,000 unmyelinated azons of large secretory neurons with cell bodies in the supraoptic & paraventricula nuclei of the hypothalamus
45
Name the most abundant cell type in the posterior pituitary gland & what do they resemble?
Pituicytes = highly branched glia cells
| They resemble= Astrocytes (star shaped glia cells of the CNS)
46
What are axonal dilations called
Neurosecretory bodies or Herring bodies = visible in the light microscope as faintly eosinophilic structures
47
Neurosecretory bodies or ______ ______ contain ______ ______ granules with either ______ or _____ bound to 10 kDa carrier protein called ____ ____ & _____
Herring Bodies
Membrane enclosed granules
Oxytocin or ADH
Neurophysin 1 & 2
48
What is released due to an increase in blood toxicity
ADH (antidiuretic hormone)
49
What type of sensory cells are present in the hypothalamus when activated during increased levels of toxicity
Osmoreceptor cells
50
What is ADH responsible for during increased levels of toxicity in the system
ADH increases the permeability of the renal collecting ducts to water, to allow more water reabsorption from the filtrate in these tubules, so that the osmotic balance of body fluids has been restored
51
Name the Hypothalamic Hormones Regulating cells of the Anterior Pit (6) & functions
1. TRH (Thyrotropin-releasing Hormone) = stimulates release of thyrotropin (TSH)
2. Gonadotropin-releasing Hormone (GnRH)= stimulates both follicle-stimulating Hormone & leutenizing Hormone
3. Somatostatin= Inhibits release of both somatotropin (GH) & TSH
4. Growth Hormone-releasing hormone (GHRH)= stimulates release of GH
5. Dopamine= inhibits release of prolactin (PRL)
6. Corticotropin-releasing hormone (CRH)= stimulates synthesis fo pro-opiomelanocortin (POMC) and release of both b-lipotropin (B-LPH) and Corticotropin (ACTH)
52
Term for frequent urination
Polyuria
53
Term for increased thirst
Polydipsia
54
Hormones of the Posterior Pituitary & function (x2)
1. ADH= Vasopressin/Antidiuretic hormone= increases h2o permeability of renal collecting ducts
2. Oxytocin= stimulates contractions of mammary gland myoephithelial cells & uterine smooth muscle
55
Adrenal glands are covered by _________ _______tissue capsule that sends thin _______ into the glands ________
Dense connective tissue capsule
Trabeculae
Parenchyma
56
The stroma consists mainly of ______ _______ supporting the secretory cells and microvasculature.
Reticula fibers
57
Adrenal glands have two concentric regions....name
1. Adrenal cortex (yellowish)
| 2. Medulla (reddish-brown)
58
Cortex arises form ________ and the medulla ________
Mesoderm
| Neural crest
59
Adrenal glands are supplied by several arteries, branches of these arteries form ________ ______
Cortical Arterioles which branch as capillaries & sinusoids that irrigate the cotes and then join the medullary capillaries Medularry arterioles
60
What penetrated directly to the medulla and form a network of fenestrated sinusoids
Medullary arterioles
61
Capillaries & Sinusoids give rise to ___ ____ ____, which join as the ____ _____ leaving the gland
Central Medullary veins
| Suprarenal Vein
62
Cells of the adrenal cortex have characteristic features of what kind of cells
Steroid-secreting cells(acidophilic cytoplasm rich in lipid droplets w/central nuclei)
63
Cells of adrenal cortex cytoplasm shown profuse smooth ___ ____ of interconnected _____ which contain the enzymes for _______ _____ and conversion of the steroid into specific active steroid hormone
Endoplasmic reticulum
Tubules
Cholesterol synthesis
Pro hormone pregnenolone
64
Adrenal cortex has 3 concentric zones in which the cords of epithelial steroid-producing cells are arranged somewhat differently, synthesizing different classes of steroid hormones.
Name 3 zones
1. Zona glomerulosa
2. Zona fasciculata
3. Zonal reticularis
65
Zona glomerulosa is found
Zona glomerulosa is most the superficial concentric zone
| -has round clusters of cells producing mineralocorticoids (aldosterone) which regulates electrolyte levels.
66
Aldosterone is produced where & what is it responsible for
By adrenal glands in the zona glomerulosa concentric zone.
| Responsible for regulating electrolyte levels
67
Middle concentric zone is know as & has ______ strands of cells producing _________ such as _______ which regulates carbohydrates metabolism
Zona Fasciculata
Elongated strands
Glucocorticoids
Cortisol
68
Inner most zone of adrenal gland is known as ______
Zona Reticularis
69
Zona Reticularis has a network of cells making the ____ ____ _____ which is converted to _______ in Men & Woman
Weak androgen dehydroepiandrosterone (DHEA)
| Testosterone
70
Adrenal Medulla contains neural crest derived _____ _____ synthesizing either ______ or ______ that regulate the stress responses.
Chromaffin cells
Epinephrine
Norepinephrine
71
Zona glomerulosa superficial to the capsule comprising _____ % of the cortex & made up of what type of cells
15%
| Closely packed, rounded arched cords of Columnar or pyramidal cells w/ many capillaries
72
Steroid made by the cells of zona glomerulosa are called ____
Mineralocorticoids-they affect the uptake of Na, K and h20 by cell of renal tubules
73
Aldosterone major regulator of salt balance stimulates Na reabsorption in the distal convoluted tubules. This Aldosterone secretion is stimulated by _____ _____ and also by an increase in plasma ______ concentration
Angiotensin II
| Plasma K concentration
74
Zona Fasciculata occupies ____% to ____% of the cortex & consists of large ______cells (one or 2 cells thick) separated by ____ _____
65%
80%
Polyhedral
Sinusoidal capillaries
75
Secretion of Cortisol is controlled by ______ with negative feedback proportional to the circulation of glucocorticoids
ACTH
76
Innermost Zone ______ comprised of ____% of cortex. Produce cortisol but primarily secrete the ____ _____, including _______ (DHEA) what is converted to testosterone in both sexes
Zona Reticularis
10%
Weak androgens
Dehydroepiandrosterone
77
Sucretion of DHEA is stimulated by ______ with regular feedback
ACTH
78
Medullary parenchymal cells are known as ____ ____ arise form ____ ____ cells
Chromaffin cells
| Neural crest cells
79
Chromaffin cell scan be considered modified ____ ____ ____, lacking _____ & dendrites and specialized as ______ cells.
Sympathetic postganglionic neurons
Axons
Secretory cells
80
Chromaffin cells contain many electron dense granules 150 to 350 no in diameter, for storage and secretion of ________ . Give example of 2
Catecholamines
| Ex: epinephrine or norepinephrine
81
Both catecholamines together with ____ & ____ are bound in granular storage complex with ____ proteins called ______
Ca+
ATP
49-kDa proteins
Chromogranins
82
The conversion of norepinephrine to epinephrine (Adrenalin) occurs only in ______ _____. Of the adrenal _______. About ____% of catecholamines secreted from the adrenal is ______
Chromaffin cells
Adrenal Medulla
80%
Epinephrine
83
```
Pancreatic islets (islets of Langerhans) are?
What type of Cell?
Produce ?
```
Small clusters of pale cells embedded within the exocrine tissue
Primarily B-Cells
Making Insulin, A-Cell (Glucagon) & Gamma cells (Somatostatin)
84
Pancreatic Islets names (x4)
Alpha cells
Beta cells
Gamma cells
PP cells (Pancreatic Polypeptide)
85
Alpha cell
| Hormone & function
Glucagon= raises blood glucose levels
86
Beta cell
| Hormone & function
Insulin=lowers blood glucose levels
87
Gamma cell
| Hormone & function
Somatostatin= inhibits secretion of insulin, glucagon, and somatotropin
88
PP cells
| Hormone & function
Pancreatic polypeptide = inhibits secretion of pancreatic enzyme & HCO-3
89
Thyroid glands (x2)
Follicular Cells= thyroid hormones (T3, T4): increases metabolic rate.
Parafollicular or C Cells= Calcitonin: lowers blood Ca+ levels by inhibiting osteoclasts activity.
90
Parathyroid glands
Endocrine cells = chief cells
Hormone= Parathyroid hormone (PTH)
Function= raises blood Ca+ levels stimulating osteoclast activity
91
Pineal Gland
Endocrine cells= Pinealocytes
Hormones= Melatonin
Function= regulates circadian rhythms
92
Diabetes Millitus characterized by what & what type is it & cause.
Loss of Insulin effect and failure of cell to take up glucose, leading to elevated blood sugar or Hyperglycemia
Type 1 Diabeter or Insulin-dependent diabetes mellitus (IDDM)
Caused by: loss of B-cells form autoimmune destruction
Tx: injection of insulin
93
Type 2 Diabetes or non-insulin dependent diabetes mellitus (NIDDM)
B-Cells are present but fail to produce adequate levels of insulin in response to hyperglycemia and the peripheral target cells “resist” or no longer respond to the hormone.
Occurs commonly with Obesity-poorly understood multifunctional genetic components.
94
Increased glucose levels stimulate _______ cells to release _______ & inhibit ___ _____from releasing glucagon.
B cells
Insulin
A Cells
95
Decreased glucose levels stimulates ___ _____ to release glucagon.
Alpha cells
96
Serotonin a neurotransmitter also known as 5-_________
5-Hydroxytryptamine
97
DNES
| Why are they important
Diffuse Neuroendocrine System
| Important due to their role in regulation motility and excretions of all types within the digestive system
98
Thyroid gland is located ______ & ______ to the larynx, consists of 2 lobes united by ______.
Anterior
Inferior
Isthmus
99
Thyroid gland originates in early embryonic life from the _____ _____
Foregut endoderm
100
Thyroid gland is described as what
Highly vascular
| Butterfly shaped glans surrounding the anterior surface of trachea just below the larynx
101
The parenchyma of the thyroid is composed of millions of rounded epithelial ____ _____ , each with simple epithelium & central lumen densely filled with _____ _____ ______.
Thyroid follicles
| Gelatinous acidophilic Colloid
102
Thyrocytes (follicular cells) have ______ _______ complexes and rest on a ______ lamina.
Apical Junctional complexes
| Basal Lamina
103
Chronic Dietary Iodine deficiencies inhibits Thyroid hormone production causing _______ _____ of the anterior pit gland to produce excess ________. Leading to excessive growth fo thyroid follicles & enlargement fo the thyroid gland, a condition know as _____.
Thyrotropic cells
TSH
Goiter
104
Decreased levels of circulation iodide trigger synthesis of NIS, increasing ______ uptake and compensating for the lower plasma concentration.
Iodine uptake
105
Define Pendrin
Apical iodide/chloride transporter, pumps I form thyrocyts into the colloid
106
What is the major regulator of the Anatomic and functional state of thyroid follicles ?
TSH (Thyrotropin) from the anterior pituitary
107
What is Graves’ disease
Autoimmune disorder in which antibodies produce chronic stimulation of the follicular cell & release of thyroid hormones (Hypothyroidism) which cause the hyper metabolic state marked by wight loss, nervousness, sweating, heat intolerance and other features.
108
Hypothyroidism defined as
With reduced thyroid hormone levels, can be caused by local inflammation (thyroid it is) of inadequate secretion of TSH by the APG.
109
Parathyroid Gland are _______ small ovoid masses. Located in back of the ______ _______,
Four small ovoid
| Back of thyroid gland
110
Parathyroid Glands are derived form the ________ ______ pouches
Embryonic pharyngeal pouches
111
Endocrine cells fo the parathyroid glands are called ____ _____
Principal Chief cells
112
Parathyroid hormone (PTH) stimulates what
PTH stimulates Ca2+ reabsorption (and inhibits phosphate reabsorption in the proximal tubules)
Also indirectly increases the Ca2+ absorption in the SI by stimulating vitamin D activation .
113
Hyperparathyroidism
Increased osteoclast activity increasing levels of blood calcium that can be deposited pathologically in cartilage, arteries or kidneys
114
Pineal Gland is also known as _________. Regulates the daily rhythms of bodily activity.
Small ______ _____ organ.
Covered by _____ ______ of the _______ matter.
Epiphysis cerebellum
Pine cone-shaped
Connective tissue
Pia matter
115
Pineal gland secretory cells are called
Pine-alocytes= slightly basophilic cytoplasm
116
Melatonin is a ________ derivative
Tryptophan
117
Pineal gland acts as a _______ _______ converting sensory input regarding light and darkness into variations in many hormonal functions.
Neuroendocrine transducer
118
Pineal gland also has _____ _____ cells that are modified ________. Usually found in ______ areas & between the groups of pinealocytes.
Interstitial glia cells
Astrocytes
Perivascular area
119
Characteristic feature of Pineal glans is the presence of variously sized concentrations of ____ and ______ salts called _____ ______ or brain sand.
Calcium
Magnesium
Corpora arenacea
