Endocrine System Flashcards
(199 cards)
1
Q
How do cells communicate?
A
Many adjacent cells form
communicating gap junctions that couple the cells and allow exchange of ions and small molecules. You can think of this as direct signaling.
2
Q
Target cells
A
Cells bearing receptors for a specific ligand. There are about 25 families of receptors.
3
Q
Types of signaling
A
Endocrine signaling, paracrine signaling, synaptic signaling, autocrine signaling, and juxtacrine signaling
4
Q
Endocrine signaling
A
The signal molecules (here called hormones) are carried in the blood from their sources to target cells throughout the body.
5
Q
Paracrine signaling
A
The chemical ligand diffuses in extracellular fluid but is rapidly metabolized so that its effect is only local on target cells near its source.
6
Q
Synaptic signaling
A
A special kind of paracrine interaction, neurotransmitters act on
adjacent cells through special contact areas called synapses.
7
Q
Autocrine signaling
A
Signals bind receptors on the same cells that produced the messenger molecule.
8
Q
Juxtacrine signaling
A
Important in embryonic tissues, the signaling molecules are cell
membrane–bound proteins which bind surface receptors of the target cell when the two cells make direct physical contact.
9
Q
Major Classes of Hormones
A
Peptides, Steroids, and Amino acid derivatives
10
Q
Peptide synthesis
A
Synthesized as prohormones, requiring further processing (e.g. cleavage) to activate
Ex. Insulin, glucagon, prolactin, ACTH, gastrin parathyroid hormone
11
Q
Steroid synthesis
A
Synthesized in a series of reactions from cholesterol
Ex. Cortisol, aldosterone, estrogen, progesterone, testosterone
12
Q
Amino acid derivatives synthesis
A
Synthesized from the amino acid tyrosine
Ex. Adrenaline, thyroxin, triiodothyronine
13
Q
Receptors
A
Many types of receptors are complex proteins that form
transmembrane structures. They communicate a signal from the outside of the cell to the inside, in various ways. This happens
when a ligand binds to the receptor on the outer surface of the cell membrane.
14
Q
Major endocrine glands
A
Pituitary gland, pineal gland, thyroid gland, and adrenal gland
15
Q
Organs containing endocrine cells
A
Hypothalamus, skin, thymus, heart, liver, stomach, pancreas, small intestine, kidney, and gonads
16
Q
Endocrine glands misc.
A
Secretory cells of endocrine glands release signaling molecules called hormones into nearby vascularized tissue for uptake distribution throughout the body.
Endocrine glands have no secretory duct as exocrine glands do.
Endocrine cells are typically of epithelial origin, and are grouped as cords or
clusters. Due to the circulatory system, hormones act on target cells at a distance.
17
Q
Pituitary gland (hypophysis)
A
The pituitary gland is composed of an anterior and a posterior that is directly attached to the hypothalamus region of the brain by an infundibular stalk. The gland occupies a fossa of the sphenoid bone called the sella turcica.
18
Q
Posterior pituitary (neurohypophysis)
A
The pars nervosa and infundibular stalk; it is a downgrowth of the brain, attached to the hypothalamus by a narrow region called the infundibulum.
Resemble CNS tissue (neural origin)
19
Q
Anterior pituitary (adenohypophysis)
A
Includes the large pars distalis and pars tuberalis that surrounds the infundibulum, and the thin pars intermedia adjacent to the pars nervosa.
Typically glandular (epithelial origin)
20
Q
What are endocrine cells of the anterior pituitary called?
A
Endocrine cells of the anterior pituitary are called acidophils, basophils, and chromophobes based on
their staining properties.
21
Q
Somatotroph cells
A
Endocrine cells in the anterior pituitary that produce somatotropin (growth hormone)
22
Q
Lactotrophs
A
Endocrine cells in the anterior pituitary that produce prolactin (PRL)
23
Q
Gonadotroph cells
A
Endocrine cells in the anterior pituitary that produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
24
Q
Thyrotroph cells
A
Endocrine cells in the anterior pituitary that produce thyroid-stimulating hormone (TSH)
25
Corticotroph cells
Endocrine cells in the anterior pituitary that synthesize pro-opiomelanocortin (POMC) that is broken up to make adrenocorticotropic hormone (ACTH) and β-lipotropic hormone (LPH).
26
Hypothalamus
The hypothalamus is the coordinating center of the endocrine system.
The hypothalamus synthesizes and secretes neurohormones, which in turn stimulate/inhibit secretion of pituitary hormones. This hypothalamic-pituitary axis directly affects the thyroid gland, adrenal gland, and gonads, and contributes to growth, lactation, and water balance.
27
Hypothalamus input
It consolidates input signals from from cortical inputs,
autonomic function, environmental cues such as light and temperature, and peripheral endocrine feedback.
28
Hypothalamus output
It controls body temperature, hunger, aspects of parenting and attachment behaviors, thirst, fatigue, sleep, and
circadian rhythms.
29
Hypothalamus target
It delivers precise signals to the pituitary gland, which releases hormones influencing most endocrine systems.
30
Hypothalamic Hormone Axes
Hormone secretion is often coordinated among
endocrine organs in sets of feedback interactions in
these four neuroendocrine systems, divided into two
"paths".
Hypothalamic–Neurohypophyseal system
Hypothalamic-Anterior Pituitary-Adrenal axis (HPA)
Hypothalamic-Anterior Pituitary-Thyroid axis (HPT)
Hypothalamic-Anterior Pituitary-Gonadal axis (HPG)
31
Hypothalamic-Neurohypophyseal tract
Consists of axons
extending from hypothalamic supraoptic and paraventricular nuclei,
through the infundibulum and into the pars nervosa of the posterior pituitary, where peptide hormones are released for capillary uptake.
32
Hypothalamic-Neurohypophyseal Hormones
Vasopressin/antidiuretic hormone (ADH) and oxytocin
33
Vasopressin/antidiuretic hormone (ADH) function
Increases water permeability of renal collecting ducts
Produced in the supraoptic nucleus of the hypothalamus
34
Oxytocin function
Stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle
Produced in the paraventricular nucleus of the hypothalamus
35
Hypothalamic-Hypophyseal Portal System
The hypothalamic-hypophyseal portal system consists of two capillary networks connected by the hypophyseal portal vein; these are the primary and the secondary plexuses
These are important in carrying hypothalamic hormones to the anterior pituitary where they control the secretion of other hormones.
36
Hypothalamic hormones
These hypothalamic hormones (also called neurohormones or releasing hormones) regulate cells of the anterior pituitary. These are peptide hormones.
Thyrotropin-releasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH)
Somatostatin/Growth hormone-inhibiting hormone
Growth hormone-releasing hormone (GHRH)
Dopamine/Prolactin-inhibiting hormone
Corticotropin-releasing hormone (CRH)
37
Thyrotropin-releasing hormone (TRH)
A hypothalamic hormone that stimulates the release of thyrotropin (TSH) from the anterior pituitary
38
Gonadotropin-releasing hormone (GnRH)
A hypothalamic hormone that stimulates the release of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary
39
Somatostatin
Also called growth hormone-inhibiting hormone
Produced in the pancreatic islets
A hypothalamic hormone that inhibits the release of both somatotropin (GH) and thyrotropin (TSH) from the anterior pituitary
40
Growth hormone-releasing hormone (GHRH)
A hypothalamic hormone that stimulates the release of somatotropin (GH) from the anterior pituitary
41
Dopamine
Also called prolactin-inhibiting hormone
A hypothalamic hormone that inhibits the release of prolactin (PRL) from the anterior pituitary
42
Corticotropin-releasing hormone (CRH)
A hypothalamic hormone that stimulates the synthesis of pro-opiomelanocortin (POMC) and the release of both β-lipotropin (LPH) and corticotropin (ACTH) (adrenocorticotropin) from the anterior pituitary.
43
Hormones of Anterior Pituitary
Seven hormones are produced. Release of these hormones is stimulated by hypothalamic peptide hormones ("releasing" hormones).
Somatotropin (GH)
Prolactin (PRL)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Thyrotropin (TSH)
Adrenal corticotropin (ACTH)
Lipotropin (LPH)
44
Somatotropin (GH)
An anterior pituitary hormone that stimulates growth in epiphyseal plates of long bones via insulin-like growth factors (IGFs) produced in the liver
45
Prolactin (PRL)
An anterior pituitary hormone that promotes milk secretion
46
Follicle-stimulating hormone (FSH)
An anterior pituitary hormone that promotes ovarian follicle development and estrogen secretion in women and spermatogenesis in men
47
Luteinizing hormone (LH)
An anterior pituitary hormone that promotes ovarian follicle maturation and progesterone secretion in women and interstitial cell androgen secretion in men (causes testis to make testosterone)
48
Thyrotropin (TSH)
An anterior pituitary hormone that stimulates thyroid hormone synthesis, storage, and liberation
49
Adrenal corticotropin (ACTH)
An anterior pituitary hormone that stimulates the secretion of adrenal cortex hormones
50
Lipotropin (LPH)
An anterior pituitary hormone that helps regulate lipid metabolism
51
Feedback Loops: Regulation
Feedback relationship between the hypothalamus, the anterior pituitary, and its target organs is shown, using the thyroid as an example.
1. Stimulus (e.g. low body temp) causes the hypothalamus to secrete thyrotropin-releasing hormone (TRH), which acts on the anterior pituitary.
2. Thyrotropic cells in the anterior pituitary release thyroid-stimulating hormone (TSH).
3. Thyroid-stimulating hormone (TSH) stimulates the follicular cells of the thyroid gland to release thyroid hormone (TH).
4. Thyroid hormone (TH) stimulates target cells to increase metabolic activities, resulting in an increase in basal body temperature.
5. Increased temperature is detected by the hypothalamus, and secretion of thyrotropin-releasing hormone (TRH) is inhibited. TH also block TRH receptors, inhibiting the release of TSH
52
Adrenal (Suprarenal) Glands
The paired adrenal
glands are located at
the superior pole of
each kidney and each
consists of
1. An outer cortex that
produces a variety of
steroid hormones
2. An inner medulla
that produces
epinephrine and
norepinephrine.
53
Adrenal Medulla
The hormone-secreting
cells of the adrenal
medulla are chromaffin
cells, which resemble
sympathetic neurons.
These make epinephrine
or norepinephrine. These
are amine-type hormones.
54
Adrenal medulla hormones
Epinephrine and norepinephrine
55
Epinephrine
A hormone produced in the adrenal medulla that increases heart rate and blood pressure
56
Norepinephrine
A hormone produced in the adrenal medulla that constricts vessels; increases heart rate and blood pressure
57
Adrenal cortex hormones
Mineralocorticoids, glucocorticoids, and weak androgens
58
Mineralocorticoids
Hormones produced in the adrenal cortex that stimulate renal reabsorption of water and Na+ and secretion of K+ to maintain salt and water balance
Aldosterone is a mineralocorticoid that is the major regulator of salt balance
59
Glucocorticoids
Hormones produced in the adrenal cortex that influence carbohydrate metabolism and suppress immune cell activities
Cortisol is a glucocorticoid which affects carbohydrate metabolism by stimulating gluconeogenesis an glycogen synthesis in the liver
60
Weak androgens
Hormones produced in the adrenal cortex that are precursors for testosterone and estrogen
61
Addison's disease
Also called adrenal cortical insufficiency and is a disorder, usually autoimmune
in origin, which causes degeneration in any layer of adrenal cortex, with concomitant loss of the associated hormones: glucocorticoids, mineralocorticoids, or androgen.
Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss. Darkening of the skin in certain areas may also occur.
62
Two main products of the
Pancreas
1. Hormones
2. Digestive enzymes
63
Pancreatic Islets
Clumped masses of pale-staining endocrine cells embedded in the exocrine acinar tissue of the pancreas.
64
Pancreatic Islets hormones
Glucagon, insulin, somatostatin, and pancreatic polypeptides
65
Glucagon
A hormone produced in the pancreatic islets that acts on several tissues to make energy stored in glycogen and fat available through glycogenolysis and lipolysis also increases blood glucose content
66
Insulin
A hormone produced in the pancreatic islets that acts on several tissues to cause entry of glucose into cells and promotes a decrease in blood glucose content
Made by β cells
67
Somatostatin
A hormone produced in the pancreatic islets that inhibits the release of other islet cell hormones through local paracrine action. Inhibits the release of somatotropin (GH) and thyrotropin (TSH) in anterior pituitary and HCl secretion by gastric parietal cells
68
Pancreatic polypeptides
A hormone produced in the pancreatic islets that stimulates activity of gastric chief cells.
Inhibits bile secretion, pancreatic enzyme and bicarbonate secretion, and intestinal motility
69
Diabetes mellitus
Characterized by loss of effect of insulin and thus failure of cells to take up glucose, leading to elevated blood sugar or hyperglycemia.
70
Type 1 diabetes or insulin-dependent diabetes mellitus
| (IDDM)
Caused by loss of the β cells (which make insulin) from autoimmune destruction and is treated by regular injections of insulin.
71
Type 2 diabetes or non–insulin-dependent diabetes
mellitus (NIDDM)
β 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. Type 2 diabetes commonly occurs with obesity, and the multifactorial genetic components are poorly understood.
72
D cells
An enteroendocrine cell
Location: Pylorus, duodenum, and pancreatic islets
Hormone produced: Somatostatin
Inhibits: Secretion from other DNES (diffuse
neuroendocrine system) cells nearby
73
Thyroid gland
The thyroid is a highly
vascular, butterfly-shaped gland surrounding the
anterior surface of the
trachea just below the
larynx.
The two major thyroid
hormones are thyroxine (T4) and tri-iodothyronine (T3),
which are involved in
metabolism
A third is calcitonin,
which regulates blood
calcium levels. Calcitonin produced by parafollicular cells
74
Thyroid hormones (T3 and T4)
Increase metabolic rate
Produced by follicular cells
75
Calcitonin
A thyroid hormone that lowers blood Ca++ levels by inhibiting osteoclast activity
76
Graves disease
An autoimmune disorder in which antibodies produce chronic stimulation of the follicular cells and release of thyroid hormones (hyperthyroidism), which
causes a hypermetabolic state marked by weight loss, nervousness, sweating, heat intolerance, and other features.
77
Hypothyroidism
With reduced thyroid hormone levels, can
be caused by local inflammation (thyroiditis) or inadequate secretion of TSH by the anterior pituitary gland and is often
manifested by tiredness, weight gain, intolerance of cold, and decreased ability to concentrate.
78
Parathyroid glands
The parathyroid glands are four small nodules normally embedded in the capsule on the posterior surface of the thyroid gland. These consist of principal cells that secrete parathyroid
hormone (PTH) and raise blood Ca++ levels.
79
Parathyroid hormone (PTH)
Produced by chief cells, this hormone raises blood Ca++ levels by stimulating osteoclast activity
In the renal cortex, it stimulates Ca++ reabsorption
80
Principal (Chief) cells
Produces parathyroid hormone (PTH)
The endocrine cells of the parathyroid glands they have cytoplasmic granules that contain the parathyroid hormone (PTH), a polypeptide, and important regulator of blood calcium levels.
81
Hypoparathyroidism
Diminished secretion of PTH can cause bones to become more mineralized and denser, and striated muscle to exhibit abnormal contractions due to inadequate calcium ion concentrations.
82
Hyperparathyroidism
Excessive PTH produced
Stimulates osteoclast number and activity, leading to increased levels of blood calcium Ca++ that can be deposited pathologically in cartilage, arteries, or the kidneys.
83
Pineal gland
The pineal gland (epiphysis cerebri) is unique in transducing sensory
input from light into effects on hormones. Pinealocytes, which are the pineal cells, are modified neurons of the brain that secrete the
neurohormone melatonin, which is amine-derived.
84
Melatonin
Produced by the pinealocytes of the pineal gland this hormone regulates circadian rhythms
85
Acromegaly is produced by overproduction of products by the cell type known as
Somatotrophs
86
What hormone do somatotrophic cells produce?
Growth hormone
87
What hormone do lactotrophic cells produce?
Prolactin
88
What hormone do gonadotrophic cells produce?
FSH, ICSH
89
What hormone do thyrotrophic cells produce?
Thyroid hormone
90
What hormone do corticotrophic cells produce?
Lipotropin (LPH)
91
Chromaffin cells of the adrenal medulla produce epinephrine and norepinephrine. The cells are functionally associated with the
Sympathetic nervous system
92
Which of these diseases is associated with obesity related to the failure of beta cells to produce sufficient insulin?
Type 2 Diabetes
93
With which organs are enteroendocrine cells associated?
Ileum, Pancreatic islets, and Duodenum
94
Which hormone stimulates growth in epiphyseal plates
Somatotropin
95
Which hormone promotes milk secretion
Prolactin
96
Which hormone promotes androgen secretion in men
ICSH
97
Which hormone stimulates secretion of adrenal cortex hormones
ACTH
98
Which hormone increases water permeability in kidney
Anti-diuretic hormone
99
Which hormone stimulates mammary gland myoepithelial cells.
Oxytocin
100
Which one of these neuroendocrine axes is associated with a reaction to stress?
Hypothalamic-Anterior Pituitary-Adrenal axis (HPA)
101
The hormones produced by the hypothalamus are
Peptides
102
What is the role of the hypothalamic-hypophyseal portal system?
It distributes releasing hormones produced by the hypothalamus to secretory cells in the anterior pituitary.
103
Which one of these parts of the brain regulates activities of the autonomic nervous system?
Hypothalamus
104
Which part of the brain manages the endocrine system?
Hypothalamus
105
Which of these hypothalamic hormones produced by the hypothalamus is inhibitory?
Dopamine and Somatostatin
106
Which is true of the pars distalis of the anterior pituitary gland?
It is highly vascularized.
107
What stimulates the pinealocytes to release melatonin?
Input from the retina.
108
The sella turcica is a cavity in which the hypophysis sits. In which bone is the sella turcica found?
Sphenoid bone.
109
The hormones vasopressin (ADH) and oxytocin are produced in the hypothalamus by certain neurosecretory cells. Into which organ do the axons of these cells release the hormones ?
Pars nervosa of the posterior pituitary gland.
110
Hypothalamic-Anterior Pituitary-Adrenal axis (HPA)
Reactions to stress. Regulates digestion, the immune system,
mood and emotions, sexuality, and energy storage and expenditure.
111
Hypothalamic-Anterior Pituitary-Thyroid axis (HPT)
Metabolism, including bone health.
112
Hypothalamic-Anterior Pituitary-Gonadal axis (HPG)
Reproductive and immune systems.
113
# Reversed prompt
Many adjacent cells form
communicating gap junctions that couple the cells and allow exchange of ions and small molecules. You can think of this as direct signaling.
How do cells communicate?
114
# Reversed prompt
Cells bearing receptors for a specific ligand. There are about 25 families of receptors.
Target cells
115
# Reversed prompt
Endocrine signaling, paracrine signaling, synaptic signaling, autocrine signaling, and juxtacrine signaling
Types of signaling
116
# Reversed prompt
The signal molecules (here called hormones) are carried in the blood from their sources to target cells throughout the body.
Endocrine signaling
117
# Reversed prompt
The chemical ligand diffuses in extracellular fluid but is rapidly metabolized so that its effect is only local on target cells near its source.
Paracrine signaling
118
# Reversed prompt
A special kind of paracrine interaction, neurotransmitters act on
adjacent cells through special contact areas called synapses.
Synaptic signaling
119
# Reversed prompt
Signals bind receptors on the same cells that produced the messenger molecule.
Autocrine signaling
120
# Reversed prompt
Important in embryonic tissues, the signaling molecules are cell
membrane–bound proteins which bind surface receptors of the target cell when the two cells make direct physical contact.
Juxtacrine signaling
121
# Reversed prompt
Peptides, Steroids, and Amino acid derivatives
Major Classes of Hormones
122
# Reversed prompt
Synthesized as prohormones, requiring further processing (e.g. cleavage) to activate
Ex. Insulin, glucagon, prolactin, ACTH, gastrin parathyroid hormone
Peptide synthesis
123
# Reversed prompt
Synthesized in a series of reactions from cholesterol
Ex. Cortisol, aldosterone, estrogen, progesterone, testosterone
Steroid synthesis
124
# Reversed prompt
Synthesized from the amino acid tyrosine
Ex. Adrenaline, thyroxin, triiodothyronine
Amino acid derivatives synthesis
125
# Reversed prompt
Many types of receptors are complex proteins that form
transmembrane structures. They communicate a signal from the outside of the cell to the inside, in various ways. This happens
when a ligand binds to the receptor on the outer surface of the cell membrane.
Receptors
126
# Reversed prompt
Pituitary gland, pineal gland, thyroid gland, and adrenal gland
Major endocrine glands
127
# Reversed prompt
Hypothalamus, skin, thymus, heart, liver, stomach, pancreas, small intestine, kidney, and gonads
Organs containing endocrine cells
128
# Reversed prompt
Secretory cells of endocrine glands release signaling molecules called hormones into nearby vascularized tissue for uptake distribution throughout the body.
Endocrine glands have no secretory duct as exocrine glands do.
Endocrine cells are typically of epithelial origin, and are grouped as cords or
clusters. Due to the circulatory system, hormones act on target cells at a distance.
Endocrine glands misc.
129
# Reversed prompt
The pituitary gland is composed of an anterior and a posterior that is directly attached to the hypothalamus region of the brain by an infundibular stalk. The gland occupies a fossa of the sphenoid bone called the sella turcica.
Pituitary gland (hypophysis)
130
# Reversed prompt
The pars nervosa and infundibular stalk; it is a downgrowth of the brain, attached to the hypothalamus by a narrow region called the infundibulum.
Resemble CNS tissue (neural origin)
Posterior pituitary (neurohypophysis)
131
# Reversed prompt
Includes the large pars distalis and pars tuberalis that surrounds the infundibulum, and the thin pars intermedia adjacent to the pars nervosa.
Typically glandular (epithelial origin)
Anterior pituitary (adenohypophysis)
132
# Reversed prompt
Endocrine cells of the anterior pituitary are called acidophils, basophils, and chromophobes based on
their staining properties.
What are endocrine cells of the anterior pituitary called?
133
# Reversed prompt
Endocrine cells in the anterior pituitary that produce somatotropin (growth hormone)
Somatotroph cells
134
# Reversed prompt
Endocrine cells in the anterior pituitary that produce prolactin (PRL)
Lactotrophs
135
# Reversed prompt
Endocrine cells in the anterior pituitary that produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
Gonadotroph cells
136
# Reversed prompt
Endocrine cells in the anterior pituitary that produce thyroid-stimulating hormone (TSH)
Thyrotroph cells
137
# Reversed prompt
Endocrine cells in the anterior pituitary that synthesize pro-opiomelanocortin (POMC) that is broken up to make adrenocorticotropic hormone (ACTH) and β-lipotropic hormone (LPH).
Corticotroph cells
138
# Reversed prompt
The hypothalamus is the coordinating center of the endocrine system.
The hypothalamus synthesizes and secretes neurohormones, which in turn stimulate/inhibit secretion of pituitary hormones. This hypothalamic-pituitary axis directly affects the thyroid gland, adrenal gland, and gonads, and contributes to growth, lactation, and water balance.
Hypothalamus
139
# Reversed prompt
It consolidates input signals from from cortical inputs,
autonomic function, environmental cues such as light and temperature, and peripheral endocrine feedback.
Hypothalamus input
140
# Reversed prompt
It controls body temperature, hunger, aspects of parenting and attachment behaviors, thirst, fatigue, sleep, and
circadian rhythms.
Hypothalamus output
141
# Reversed prompt
It delivers precise signals to the pituitary gland, which releases hormones influencing most endocrine systems.
Hypothalamus target
142
# Reversed prompt
Hormone secretion is often coordinated among
endocrine organs in sets of feedback interactions in
these four neuroendocrine systems, divided into two
"paths".
Hypothalamic–Neurohypophyseal system
Hypothalamic-Anterior Pituitary-Adrenal axis (HPA)
Hypothalamic-Anterior Pituitary-Thyroid axis (HPT)
Hypothalamic-Anterior Pituitary-Gonadal axis (HPG)
Hypothalamic Hormone Axes
143
# Reversed prompt
Consists of axons
extending from hypothalamic supraoptic and paraventricular nuclei,
through the infundibulum and into the pars nervosa of the posterior pituitary, where peptide hormones are released for capillary uptake.
Hypothalamic-Neurohypophyseal tract
144
# Reversed prompt
Vasopressin/antidiuretic hormone (ADH) and oxytocin
Hypothalamic-Neurohypophyseal Hormones
145
# Reversed prompt
Increases water permeability of renal collecting ducts
Produced in the supraoptic nucleus of the hypothalamus
Vasopressin/antidiuretic hormone (ADH) function
146
# Reversed prompt
Stimulates contraction of mammary gland myoepithelial cells and uterine smooth muscle
Produced in the paraventricular nucleus of the hypothalamus
Oxytocin function
147
# Reversed prompt
The hypothalamic-hypophyseal portal system consists of two capillary networks connected by the hypophyseal portal vein; these are the primary and the secondary plexuses
These are important in carrying hypothalamic hormones to the anterior pituitary where they control the secretion of other hormones.
Hypothalamic-Hypophyseal Portal System
148
# Reversed prompt
These hypothalamic hormones (also called neurohormones or releasing hormones) regulate cells of the anterior pituitary. These are peptide hormones.
Thyrotropin-releasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH)
Somatostatin/Growth hormone-inhibiting hormone
Growth hormone-releasing hormone (GHRH)
Dopamine/Prolactin-inhibiting hormone
Corticotropin-releasing hormone (CRH)
Hypothalamic hormones
149
# Reversed prompt
A hypothalamic hormone that stimulates the release of thyrotropin (TSH) from the anterior pituitary
Thyrotropin-releasing hormone (TRH)
150
# Reversed prompt
A hypothalamic hormone that stimulates the release of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary
Gonadotropin-releasing hormone (GnRH)
151
# Reversed prompt
Also called growth hormone-inhibiting hormone
Produced in the pancreatic islets
A hypothalamic hormone that inhibits the release of both somatotropin (GH) and thyrotropin (TSH) from the anterior pituitary
Somatostatin
152
# Reversed prompt
A hypothalamic hormone that stimulates the release of somatotropin (GH) from the anterior pituitary
Growth hormone-releasing hormone (GHRH)
153
# Reversed prompt
Also called prolactin-inhibiting hormone
A hypothalamic hormone that inhibits the release of prolactin (PRL) from the anterior pituitary
Dopamine
154
# Reversed prompt
A hypothalamic hormone that stimulates the synthesis of pro-opiomelanocortin (POMC) and the release of both β-lipotropin (LPH) and corticotropin (ACTH) (adrenocorticotropin) from the anterior pituitary.
Corticotropin-releasing hormone (CRH)
155
# Reversed prompt
Seven hormones are produced. Release of these hormones is stimulated by hypothalamic peptide hormones ("releasing" hormones).
Somatotropin (GH)
Prolactin (PRL)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Thyrotropin (TSH)
Adrenal corticotropin (ACTH)
Lipotropin (LPH)
Hormones of Anterior Pituitary
156
# Reversed prompt
An anterior pituitary hormone that stimulates growth in epiphyseal plates of long bones via insulin-like growth factors (IGFs) produced in the liver
Somatotropin (GH)
157
# Reversed prompt
An anterior pituitary hormone that promotes milk secretion
Prolactin (PRL)
158
# Reversed prompt
An anterior pituitary hormone that promotes ovarian follicle development and estrogen secretion in women and spermatogenesis in men
Follicle-stimulating hormone (FSH)
159
# Reversed prompt
An anterior pituitary hormone that promotes ovarian follicle maturation and progesterone secretion in women and interstitial cell androgen secretion in men (causes testis to make testosterone)
Luteinizing hormone (LH)
160
# Reversed prompt
An anterior pituitary hormone that stimulates thyroid hormone synthesis, storage, and liberation
Thyrotropin (TSH)
161
# Reversed prompt
An anterior pituitary hormone that stimulates the secretion of adrenal cortex hormones
Adrenal corticotropin (ACTH)
162
# Reversed prompt
An anterior pituitary hormone that helps regulate lipid metabolism
Lipotropin (LPH)
163
# Reversed prompt
Feedback relationship between the hypothalamus, the anterior pituitary, and its target organs is shown, using the thyroid as an example.
1. Stimulus (e.g. low body temp) causes the hypothalamus to secrete thyrotropin-releasing hormone (TRH), which acts on the anterior pituitary.
2. Thyrotropic cells in the anterior pituitary release thyroid-stimulating hormone (TSH).
3. Thyroid-stimulating hormone (TSH) stimulates the follicular cells of the thyroid gland to release thyroid hormone (TH).
4. Thyroid hormone (TH) stimulates target cells to increase metabolic activities, resulting in an increase in basal body temperature.
5. Increased temperature is detected by the hypothalamus, and secretion of thyrotropin-releasing hormone (TRH) is inhibited. TH also block TRH receptors, inhibiting the release of TSH
Feedback Loops: Regulation
164
# Reversed prompt
The paired adrenal
glands are located at
the superior pole of
each kidney and each
consists of
1. An outer cortex that
produces a variety of
steroid hormones
2. An inner medulla
that produces
epinephrine and
norepinephrine.
Adrenal (Suprarenal) Glands
165
# Reversed prompt
The hormone-secreting
cells of the adrenal
medulla are chromaffin
cells, which resemble
sympathetic neurons.
These make epinephrine
or norepinephrine. These
are amine-type hormones.
Adrenal Medulla
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Epinephrine and norepinephrine
Adrenal medulla hormones
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A hormone produced in the adrenal medulla that increases heart rate and blood pressure
Epinephrine
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A hormone produced in the adrenal medulla that constricts vessels; increases heart rate and blood pressure
Norepinephrine
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Mineralocorticoids, glucocorticoids, and weak androgens
Adrenal cortex hormones
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Hormones produced in the adrenal cortex that stimulate renal reabsorption of water and Na+ and secretion of K+ to maintain salt and water balance
Aldosterone is a mineralocorticoid that is the major regulator of salt balance
Mineralocorticoids
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Hormones produced in the adrenal cortex that influence carbohydrate metabolism and suppress immune cell activities
Cortisol is a glucocorticoid which affects carbohydrate metabolism by stimulating gluconeogenesis an glycogen synthesis in the liver
Glucocorticoids
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Hormones produced in the adrenal cortex that are precursors for testosterone and estrogen
Weak androgens
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Also called adrenal cortical insufficiency and is a disorder, usually autoimmune
in origin, which causes degeneration in any layer of adrenal cortex, with concomitant loss of the associated hormones: glucocorticoids, mineralocorticoids, or androgen.
Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss. Darkening of the skin in certain areas may also occur.
Addison's disease
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1. Hormones
2. Digestive enzymes
Two main products of the
Pancreas
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Clumped masses of pale-staining endocrine cells embedded in the exocrine acinar tissue of the pancreas.
Pancreatic Islets
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Glucagon, insulin, somatostatin, and pancreatic polypeptides
Pancreatic Islets hormones
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A hormone produced in the pancreatic islets that acts on several tissues to make energy stored in glycogen and fat available through glycogenolysis and lipolysis also increases blood glucose content
Glucagon
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A hormone produced in the pancreatic islets that acts on several tissues to cause entry of glucose into cells and promotes a decrease in blood glucose content
Made by β cells
Insulin
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A hormone produced in the pancreatic islets that inhibits the release of other islet cell hormones through local paracrine action. Inhibits the release of somatotropin (GH) and thyrotropin (TSH) in anterior pituitary and HCl secretion by gastric parietal cells
Somatostatin
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A hormone produced in the pancreatic islets that stimulates activity of gastric chief cells.
Inhibits bile secretion, pancreatic enzyme and bicarbonate secretion, and intestinal motility
Pancreatic polypeptides
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Characterized by loss of effect of insulin and thus failure of cells to take up glucose, leading to elevated blood sugar or hyperglycemia.
Diabetes mellitus
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Caused by loss of the β cells (which make insulin) from autoimmune destruction and is treated by regular injections of insulin.
Type 1 diabetes or insulin-dependent diabetes mellitus
| (IDDM)
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β 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. Type 2 diabetes commonly occurs with obesity, and the multifactorial genetic components are poorly understood.
Type 2 diabetes or non–insulin-dependent diabetes
mellitus (NIDDM)
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An enteroendocrine cell
Location: Pylorus, duodenum, and pancreatic islets
Hormone produced: Somatostatin
Inhibits: Secretion from other DNES (diffuse
neuroendocrine system) cells nearby
D cells
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The thyroid is a highly
vascular, butterfly-shaped gland surrounding the
anterior surface of the
trachea just below the
larynx.
The two major thyroid
hormones are thyroxine (T4) and tri-iodothyronine (T3),
which are involved in
metabolism
A third is calcitonin,
which regulates blood
calcium levels. Calcitonin produced by parafollicular cells
Thyroid gland
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Increase metabolic rate
Produced by follicular cells
Thyroid hormones (T3 and T4)
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A thyroid hormone that lowers blood Ca++ levels by inhibiting osteoclast activity
Calcitonin
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An autoimmune disorder in which antibodies produce chronic stimulation of the follicular cells and release of thyroid hormones (hyperthyroidism), which
causes a hypermetabolic state marked by weight loss, nervousness, sweating, heat intolerance, and other features.
Graves disease
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With reduced thyroid hormone levels, can
be caused by local inflammation (thyroiditis) or inadequate secretion of TSH by the anterior pituitary gland and is often
manifested by tiredness, weight gain, intolerance of cold, and decreased ability to concentrate.
Hypothyroidism
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The parathyroid glands are four small nodules normally embedded in the capsule on the posterior surface of the thyroid gland. These consist of principal cells that secrete parathyroid
hormone (PTH) and raise blood Ca++ levels.
Parathyroid glands
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Produced by chief cells, this hormone raises blood Ca++ levels by stimulating osteoclast activity
In the renal cortex, it stimulates Ca++ reabsorption
Parathyroid hormone (PTH)
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Produces parathyroid hormone (PTH)
The endocrine cells of the parathyroid glands they have cytoplasmic granules that contain the parathyroid hormone (PTH), a polypeptide, and important regulator of blood calcium levels.
Principal (Chief) cells
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Diminished secretion of PTH can cause bones to become more mineralized and denser, and striated muscle to exhibit abnormal contractions due to inadequate calcium ion concentrations.
Hypoparathyroidism
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Excessive PTH produced
Stimulates osteoclast number and activity, leading to increased levels of blood calcium Ca++ that can be deposited pathologically in cartilage, arteries, or the kidneys.
Hyperparathyroidism
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The pineal gland (epiphysis cerebri) is unique in transducing sensory
input from light into effects on hormones. Pinealocytes, which are the pineal cells, are modified neurons of the brain that secrete the
neurohormone melatonin, which is amine-derived.
Pineal gland
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Produced by the pinealocytes of the pineal gland this hormone regulates circadian rhythms
Melatonin
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Reactions to stress. Regulates digestion, the immune system,
mood and emotions, sexuality, and energy storage and expenditure.
Hypothalamic-Anterior Pituitary-Adrenal axis (HPA)
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Metabolism, including bone health.
Hypothalamic-Anterior Pituitary-Thyroid axis (HPT)
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Reproductive and immune systems.
Hypothalamic-Anterior Pituitary-Gonadal axis (HPG)
