Endocrine and Blood (16/19) Flashcards
1
Q
Endocrine system
A
The group of organs that secretes hormones influencing functions of other cells and tissues
2
Q
Hormones
A
chemical messenger sent into the blood that triggers changes within its target cells
3
Q
“endo”
A
“within” as in “within the blood”
4
Q
Blood capillaries
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cells of tiny blood vessels
5
Q
Hormone secretion and distribution by the blood
A
- hormones are secreted into interstitial fluid, after which they diffuse into blood capillaries
- Blood transports hormones to the heart through the veins
- after leaving the heart, the blood transports the hormones to the rest of the body through the arteries
- in capillary beds, the hormones diffuse out of the blood, into the interstitial fluid, and bind to receptors on their target cells.
6
Q
Paracrine
A
chemical messenger secreted into extracellular fluid to influence nearby target cells
7
Q
Autocrine
A
chemical messenger that influences function of same cell or cell type that produced or secreted it
8
Q
Endocrine glands consist of..
A
ductless glandular epithelial cells that secrete their hormones into the interstitial fluid for transport by the bloodstream
9
Q
Exocrine glands
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secrete their products into ducts that lead to body surfaces or cavities
10
Q
Endocrine organs
A
- anterior pituitary gland
- thyroid gland
- parathyroid gland
- thymus gland
- adrenal cortex
- pancreas
- ovaries
- testes
11
Q
anterior pituitary gland
A
situated in sphenoid bone of the skull
12
Q
thyroid gland
A
in anterior neck
13
Q
3-5 small parathyroid glands
A
found on posterior thyroid gland
14
Q
paired adrenal cortices
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located on the superior surface of the kidneys
15
Q
endocrine pancreas
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found in the left side of the abdominal cavity mostly posterior to the stomach
16
Q
thymus
A
located in the superior mediastinum
17
Q
paired ovaries or testes
A
the former in the pelvic cavity in women and the latter suspended below the pelvic cavity in men
18
Q
neuroendocrine organs
A
an organ that consists of nervous tissue but also secretes hormones
(hypothalamus and pineal gland (brain), adrenal medulla in core of adrenal gland)
19
Q
Paraneoplastic syndrome
A
‘the signs and symptoms that accompany hormone secretion from cancer cells’
common findings include imbalances in fluid, calcium ion, and sodium ion homeostasis
symptoms - precede other symptoms of cancer and investigating them may lead to an earlier diagnosis
20
Q
amino acid-based hormones
A
chemical messenger consisting of one or more amino acids; most of these hormones are hydrophilic and bind plasma membrane receptors.
produced by anterior pituitary gland, pancreas, thymus, thyroid, and parathyroid glands, consist of one or more amino acids.
21
Q
Which amino acid-based hormone is not hydrophilic?
A
thyroid hormone is hydrophobic aa, tyrosine, and does not freely interact with water.
22
Q
Steroid hormones
A
Chemical messengers derived from cholesterol, with a core of hydrocarbon rings; hydrophobic and interact with plasma membrane or intracellular receptors
adrenal cortex, testes, and ovaries
23
Q
lipid-soluble
A
can mix with fats and can be stored in adipose tissue
24
Q
Free hormones
A
small, aa-based hormones that are hydrophilic and able to freely associate with water. hydrophilic nature allows them to travel freely through the water-based plasma of blood
25
bound hormones
which form complexes with binding proteins in the plasma, are usually hydrophobic and so do not associate with the water molecules in plasma
26
Receptors
the hormones can bind, receptors have 3D shapes that are highly specific for their hormones, and can bind to hormones present at extremely low concentration.
27
upregulation
when the level of a particular hormone in the blood declines, target cells will make more receptors for the hormone, thereby increasing the cells' sensitivity to the hormone
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downregulation
prolonged exposure to a high level of a given hormone causes the opposite effect - target cells decrease the number of receptors specific for that hormone
29
G-protein
When a hormone binds to a receptor linked to a G-protein, the G-protein changes shape and dissociates into two subunits. The G-protein subunit may activate or inhibit the enzyme, depending on which G-protein has been activated. if activated - catalyzes the formation of a second messenger, which then initiates a series of changes in the cell that lead to some change in its activity
30
steps of adenylate cyclase - cAMP system
1. hydrophilic hormone (first messenger) binds to its receptor in the plasma membrane, causing the G-protein to split into two subunits
2. the G-protein subunit activates adenylate cyclase
3. adenylate cyclase catalyzes the formation of cAMP, the second messenger
4. cAMP activates protein kinase A
5. Protein kinase A phosphorylates specific proteins
31
mechanism of action of hydrophobic hormones via binding an intracellular receptor
1. hydrophobic hormone diffuses into the target cell
2. hormone binds to an intracellular receptor and enters the nucleus of the cell
3. hormone-receptor complex interacts with the DNA to initiate a cellular change
32
effects of hormone action -
-stimulating secretion from an endocrine or exocrine cell
- activating or inhibiting enzymes
- stimulating or inhibiting mitosis and/or meiosis
- opening or closing ion channels in the cell's plasma membrane and/or altering its membrane potential
- activating or inhibiting transcription of genes that code for RNA or proteins
33
half life
the amount of time it takes for the plasma concentration of the hormone to reduce by half
34
hormonal stimuli
Some endocrine cells increase or decrease their secretion in response to other hormones
two hypothalamic hormones: growth hormone–releasing hormone and somatostatin, which stimulate and inhibit secretion of growth hormone from the anterior pituitary gland, respectively.
35
humoral stimuli
Many endocrine cells respond to the concentration of a certain ion or compound in the blood or extracellular fluid, such as glucose or calcium ions.
pancreas releasing the hormone insulin in response to an elevated level of glucose in the blood.
36
Neural stimuli
some cells respond to signals from the nervous system
example of this is the adrenal medulla, which is stimulated by sympathetic neurons to release the neurohormones epinephrine and norepinephrine
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Stimulus
A regulated physiological variable deviates from its normal range.
38
Receptor
Receptors on endocrine cells detect the deviation of the variable.
39
Control center
The stimulated control center (often the same endocrine cell) increases or decreases its secretion of a particular hormone.
40
Effector/response
The hormone triggers a response in its target cells that moves conditions toward the normal range.
41
Homeostatic range
As the variable returns to its normal range, feedback to the control center decreases the effector response.
42
hypothalamus
small anteroinferior portion of the diencephalon of the brain. connected to the pituitary gland by a stalk called the infundibulum.
43
pituitary gland
small organ, size of a bean, that sits in the sella turcica of the sphenoid bone
44
anterior pituitary gland/ adenohypophysis
Derived from glandular epithelium; produces many tropic hormones and growth hormone
45
Posterior pituitary gland/ neurohypophysis
derived from nervous tissue; stores ADH and oxytocin produced by the hypothalamus
46
portal veins
capillaries merge in the hypothalamus to form larger blood vessels (PORTAL VEINS) that travel through the infundibulum. These veins lead to a second group of capillaries in the anterior pituitary gland
47
posterior pituitary hormones
releases and stores 2 neurohormones by clusters of cell bodies in the hypothalamus, known as supraoptic and paraventricular nuclei. = Antidiuretic hormone (ADH) and oxytocin
48
ADH
that controls water balance; produced by hypothalamus and stored in posterior pituitary that causes the insertion of aquaporin channels in the cells of the distal tubule and collecting system to allow water reabsorption
* to increase the amount of water retained by the kidneys
49
ADH synthesis and release
1. hypothalamic neurons make ADH
2. ADH travels through the hypothalamic-hypophyseal tract in the infundibulum
3. ADH is stored in the axon terminals in the posterior pituitary
4. ADH is secreted into the capillaries in the posterior pituitary when the hypothalamic neurons fire action potentials
50
primary function of ADH
increase the amount of water retained by the kidneys
51
Diabetes insipidus
an abnormal lack of ADH secretion or activity results this disease
52
oxytocin
produced by the hypothalamus and stored in the axon terminals of the posterior pituitary gland. Functions are primarily reproductive. Specialized cells of the mammary glands and the smooth muscle cells of the uterus.
53
Thyroid stimulating hormone (TSH)
anterior pituitary hormone that stimulates the production and release of thyroid hormone and growth of the thyroid gland
54
Somatostatin
hormone from hypothalamus that inhibits the release of growth hormone from anterior pituitary gland
55
adrenocorticotropic hormone (ACTH)
hormone released by the adrenal cortex that stimulates production of mostly glucocorticoids from adrenal cortex
56
Prolactin
effects are tropic but primary target tissue is mammary gland cells, where its effects are non-tropic. secretion is inhibited by the hypothalamic inhibiting hormone prolactin-inhibiting factor, now known to be dopamine.
57
Luteinizing hormone (LH)
hormone from anterior pituitary that stimulates reproductive functions in male and females
58
GnRH (gonadotropin-releasing hormone)
LH secretion is stimulated by the hypothalamic releasing hormone
59
Follicle-stimulating hormone (FSH)
hormone from anterior pituitary that stimulates reproductive functions in males and females (gonadotropin)
60
growth hormone (GH)
hormone produced by anterior pituitary that stimulates fat breakdown and gluconeogenesis; also stimulates insulin-like growth factor which promotes growth and protein synthesis
(somatotropin)
61
insulin like growth factor (IGF)
hormone produced largely by the liver in response to growth hormone; promotes cell division and protein synthesis
62
Growth hormone releasing hormone (GHRH)
stimulates release of GH, and its secretion increases during exercise, fasting, and stress, and after the ingestion of a protein-rich meal. inhibited by the hypothalamic hormone somatostatin - growth hormone inhibiting hormone
63
thyroid gland
endocrine gland in anterior of neck that secretes thyroid hormones and calcitonin
64
thyroid hormones
regulate growth and metabolism
65
calcitonin
helps to regulate calcium ion homeostasis.
66
parathyroid hormone
major player in maintaining level of calcium ions in the ECF within the normal range
67
thyroid follicles
spherical subunit of thyroid gland in which thyroid hormones are produced and stored
68
parafollicular cells produce..
produce hormone calcitonin
69
parathyroid glands
3-5 small endocrine glands located on posterior thyroid gland; produced parathyroid hormone
70
Triiodothyronine (T3)
hormone produced in thyroid gland that has 3 iodine atoms; promotes growth and development, regulates metabolic rate and heat production, promotes effects of sympathetic nervous system on target cells
71
Thyroxine (T4)
hormone from pituitary gland that has 4 iodine atoms; less active form and can be converted into T3 by cells when needed
72
effects of thyroid hormones
1. regulation of the metabolic rate and thermoregulation
2. promotion of growth and development,
3. synergism with the sympathetic nervous system
73
Thyroid hormone production
1. iodide ions and thyroglobulin are secreted into the colloid
2. iodide ions are converted to iodine atoms that attach to thyroglobulin
3. iodinated thyroglobulin enters the follicle cell by endocytosis, and T3 and T4 are cleaved from the molecule in reactions catalyzed by lysosomal enzymes.
4. T3 and T4 are released into the blood
74
Hyperthyroidism
overproduction of thyroid hormones
75
Hypothyroidism
underproduction of thyroid hormones
76
Graves' disease
most common cause of hyperthyroidism. results from the immune system producing abnormal proteins that mimic the actions of TSH on the thyroid gland. Abnormal proteins stimulate the thyroid and levels of both T3 and T4 in the blood increase.
77
signs of graves' disease
1. weight loss due to an elevated metabolic rate
2. heat intolerance due to excessive heat production
3. disruptions in heart rhythm and increase in bp due to the synergism of thyroid hormones with the sympathetic nervous system.
78
Goiter
enlargement of thyroid gland - final sign of hyperthyroidism
79
signs and symptoms of hypothyroidism
1. weight gain due to a decreased metabolic rate
2. cold intolerance due to decreased heat production
3. slow heart rate and low BP due to decreased synergism with the sympathetic nervous system
80
parathyroid hormone
hormone produced in parathyroid hormone that increases concentration of calcium ions in the extracellular fluid. released in response to a declining blood calcium ion concentration, hypocalcemia.
81
effects of parthyroid hormone
- increasing release of calcium ions from bone by stimulating osteoclasts
- increasing absorption of dietary calcium ions by the small intestine
- increasing reabsorption of calcium ions from the fluid in the kidneys.
82
Calcitonin
in response to hypercalcemia, produced by the thyroid gland's parafollicular cells, decreases the blood calcium ion concentration. primary actions involve inhibiting the activity of the osteoclasts in bone.
83
adrenal glands
an endocrine gland located on top of each kidney (superior pole); consist of an outer cortex and inner medulla
84
adrenal cortex
outer region of adrenal gland that produces steroid hormones
85
adrenal medulla
Inner region of adrenal gland; consists of chromaffin cells that release Norepinephrine and epinephrine when stimulated by sympathetic nervous system
86
adrenal cortex zones
outer - zona glomerulosa (densely packed cells)
middle- zona fasciculata (cells stacked on top of one another in columns)
inner - zona reticularis (cells are thin and arranged more loosely in clusters)
87
zona glomerulosa cells produce hormones =
mineralocorticoids
88
mineralocorticoids
regulate the concentration of certain minerals in the body (main one is aldosterone)
89
aldosterone
hormone produced by adrenal cortex and increases reabsorption of sodium ions from distal tubule and secretion of potassium and hydrogen ions
90
effects of aldosterone
- maintain the concentrations of extracellular sodium and potassium ions within their normal ranges
- regulating extracellular fluid volume
- maintaining BP
- maintaining acid-base homeostasis
91
effects of cortisol
- gluconeogenesis in the liver
- release of amino acids from muscle tissue
- release of fatty acids from adipose tissue
92
chromaffin cells
derived from nervous tissue rather than glandular tissue. in adrenal medulla that secrete epinephrine and norepinephrine when stimulated by sympathetic nervous system
93
epinephrine and norepinephrine effect on stressor
- increasing rate and force of heart contraction
- dilating the bronchioles
- constricting the blood vessels supplying the skin, digestive organs, and urinary organs
- dilating the blood vessels supplying skeletal muscles
- dilating the pupils
- decreasing digestive and urinary functions
94
hormones of adrenal gland
aldosterone - mineralocorticoids
cortisol - glucocorticoids
androgens - androgenic steroids
catacholamines - epinephrine and norepinephrine
95
alpha cells
glucagon secretion
96
beta cells
insulin secretion
97
delta cells
secrete somatostatin (also from hypothalamus)
98
plasma
the liquid extracellular matrix; and formed elements, the cells and cell fragments that are suspended in plasma.
99
hematocrit
portion of blood with erythrocytes
100
blood functions
1. exchanging gases
2. distributing solutes
3. performing immune functions
4. maintaining body temperature
5. sealing damaged vessels by forming blood clots
6. preserving acid-base homeostasis
7. stabilizing bp
101
albumin
the most abundant plasma protein; largely responsible for the colloid osmotic pressure
102
antibodies
a protein from activated b lymphocytes that binds to a specific antigen and facilitates its removal from a tissue
103
hematocrit %
males - 40-50%
females - 36-44% due to male's larger body size and greater muscle and bone mass
104
erythrocyte
a biconcave disc; that transports oxygen and carbon dioxide on its hemoglobin
105
oxyhemoglobin
heme binds to oxygen in parts of the body where the oxygen level is high
106
deoxyhemoglobin
when oxygen levels are low, as in the tissues surrounding systemic capillaries, hemoglobin releases oxygen
107
erythrocyte lifespan
100-120 days because they lack the cellular machinery to repair damage and the body must continuously make new erythrocytes
108
hematopoiesis
the process that produces the formed elements in blood, occurs in red bone marrow which houses the cells from which formed elements arise - the hematopoietic stem cells
109
erythropoiesis
the formation of erythrocytes, part of the larger process of hematopoiesis
110
formation of erythrocytes
hematopoietic stem cell, erythrocyte-CFU, proerythroblast, early erythroblast, late erythroblast, reticulocyte, erythrocyte
111
reticulocytes
an immature erythrocyte released into circulation that still has a nucleus and some organelles
112
negative feedback loop regulating erythropoiesis
stimulus: the blood oxygen level decreases below normal range
receptor: kidney cells detect a low oxygen level
control center: kidneys produce more erythropoietin and release it into the blood
effector/response: production of erythrocytes increases
homeostasis: the blood level of oxygen rises to normal
113
iron-deficiency anemia
due to inadequete dietary iron, reduced intestinal absorption of dietary iron, or slow blood loss
114
pernicious anemia
results from vitamin B12 deficiency, which interferes with DNA synthesis of rapidly dividing cells, including hematopoietic cells in bone marrow
115
hemolytic anemia
erythrocyte destruction can lead to this. causes can include bacterial infections, diseases of the immune system or liver, and lead poisoning. the red bone marrow may stop producing erythrocytes, which results in aplastic anemia.
116
aplastic anemia
red bone marrow may stop producing erythrocytes. certain medications or exposure to ionizing radiation may indue this but the cause is still unknown.
117
granulocytes
contain cytoplasmic granules that the cells release when activated (neutrophil, eosinophil, basophil)
118
agranulocytes
lack visible cytoplasmic granules. (lymphocytes, monocyte)
119
neutrophils
most common type of leukocyte, 60% of total leukocytes in the blood. nuclei have 3-5 variably shaped lobes, (polymorphonucleocytes)
120
chemotaxis
a process where cells are attracted to a particular location in the body due to the chemicals released.
121
eosinophils
relatively rare luekocytes that account for fewer than 3% of total leukocytes in the blood. their nuclei are bilobed, resembling a barbell, with two circular lobes connected by a thin strand of nuclear material
122
basophils
least common leukocyte, make up less than 1% of total leukocytes in the blood. almost completely obscure the typically s-shaped nuclei in these cells. release chemicals that mediate inflammation!
123
lymphocytes
make up 30-34% of total leukocytes in the blood. they contain large, spherical nuclei and generally a thin rim of light blue cytoplasm that visible when stained
124
platelet lifespan
7-10 days. when reached old age, the liver and spleen remove them from circulation
125
hemostasis
the process of blood stopping by a damaged blood vessel
126
hemostasis steps
1. vascular spasm
2. platelet plug formation
3. coagulation
4. clot retraction
5. thrombolysis
127
universal recipient
AB+
128
Universal donor
O-
