Chapter 11 Endocrine glands Flashcards
1
Q
How many types of Hormones are there
A
4
2
Q
What is the endocrine system
A
System of endocrine glands that secrete hormones and hormone secreting cells in various organs
3
Q
What is a gland
A
Group of epithelial cells or an organ that synthesizes and secretes chemical substances
4
Q
What is special about endocrine glands
A
Ductless
Secrete hormones into bloodstream
Travel to target cells
5
Q
What is special about exocrine glands
A
Ducted
6
Q
What is a hormone
A
A biologically active molecule that serves as a chemical messenger in the blood
7
Q
What are the major endocrine glands in the body
A
Pineal gland Hypothalamus Pituitary gland Thyroid gland Adrenal gland Pancreas Ovary Testis
8
Q
Where are the Islets of Langerhands located and what do they secrete
A
Pancreas
Secrete insulin and glucagon
9
Q
What are the 4 types of hormones
A
Amines
Polypeptides/protein hormones
Glycoproteins
Steroids
10
Q
What are Amines are derived from
A
Tyrosine and Tryptophan
11
Q
What hormones are Amines
A
Thyroid hormones
Catecholamines (E, NE, Dopamine)
12
Q
What secretes E and NE
A
Adrenal medulla
13
Q
What secretes Dopamine
A
Hypothalamus
14
Q
What secretes melatonin
A
Pineal gland
15
Q
What do most hormones come under
A
Polypeptides and Protein hormones
16
Q
What is a Prohormone
A
Inactive percursor molecule
17
Q
What is the process of cleavage during packaging and after secretion
A
Modification
18
Q
What type of hormone is a protein that is bound to carbohydrate
A
Glycoproteins
19
Q
What are lipid based hormones
A
Steroids
20
Q
What secretes corticosteroids
A
Adrenal cortex
21
Q
What secretes sex steroids
A
Adrenal cortex
Gonads
22
Q
What 4 steroid hormones derive from cholesterol
A
Progesterone
Cortisol
Testosterone
Estradiol
23
Q
What is special about the synthesis and secretion of steroids
A
It is simultaneous
24
Q
What 3 inputs to endocrine cells can stimulate or inhibit a hormones secretion
A
Mineral ions
Neurotransmitter
Hormones
25
What hormones dissolve in the plasma (are water soluble/polar)
Polypeptides
Glycoproteins
Catecholamines
26
What hormones are lipid-soluble (non polar)
Steroids
| Thyroid hormones
27
Where do polar hormones bind
To receptors on the plasma membrane
28
Where do non polar hormones bind
To receptors in cytosol of target cells after dissociating from carrier proteins
29
What is synergism
When 2+ hormones work together to produce a result
E.g.
Additive effects of E and NE in the heart to increase cardiac rate
30
What is Permissiveness
When hormone (A) must be present in order for hormone (B) to be fully effective
31
What is Up-regulation (priming)
Increase in number of receptors for a hormone because of long exposure to low concentration of hormone
32
What does Up-regulation cause
Increase in reponsiveness of the target cell to that hormone
33
What is the opposite of Up-regulation
Down-regulation (desensitisation)
34
What does this opposite effect cause
Decrease responsiveness of the target cell to that hormone to prevent overstimulation
35
What two things does the concentration of hormones in blood depend on
Rate of secretion
| Rate of removal
36
What ways do we remove stuff
Excretion (kidneys)
| Inactivation by metabolism (liver)
37
What does the posterior pituitary gland do
Releases and stores hormones produced in the Hypothalamus
38
What does the anterior pituitary gland do
Produces and secretes hormones
Is regulated by hypothalamic hormones
39
What allows the transport of hormones from the hypothalamus to the posterior pituitary capillaries
Axons in the Hypothalamic hypophyseal tract
40
List the pathway of a hormone in the hypothalamus to the Posterior Pituitary then to the organs
1. Peptide hormones packaged
2. Exocytosis
3. Enters capillaries
4. Release from storage in posterior pituitary by AP
5. Heart pumps blood with hormone to organs
41
What are the two posterior pituitary hormones
What are their function
Oxytocin = acts on smooth muscle in breast and uterus
Vasopressin (ADH) = acts on vascular smooth muscle to increase blood pressure (constriction) and on kidnet collecting ducts to retain fluids
42
List the pathway of a hormone in the hypothalamus to the anterior pituitary gland
Hormone transported via blood vessels in the hypothalamo-hypophyseal portal system to anterior pituitary
Hormone binds to receptors on the anterior pituitary
Secretion of anterior pituitary hormones into blood circulation
43
What do tropic hormones do and where are they produced
Produced in hypothalamus
Regulate secretion of all anterior pituitary hormones
44
Explain the 3 - hormone sequence of the anterior pituitary
1. Hypophysiotropic hormone secreted from Hypothalamic neuron into the Hypothalamo-hypophyseal portal system
This controls secretion of....
2. an Anterior pituitary hormone
Which controls secretion of...
3. A hormone in another gland
Which effects....
4. Target cell
45
Steps of hypothalamus - pituitary - thyroid axis
TRH (Thyrotopin releasing hormone) stimulates...
which stimulates the secretion of TSH (anterior pituitary)
which stimulates the secretion of thyroxine (thyroid)
46
What does the increase in thyroxine cause
1. Negative feedback loop
| 2. Inhibits responsiveness of TRH and secretion
47
Steps of hypothalamus - pituitary - gonad axis
GnRH stimulates secretion of FSH and LH
Which stimulates the secretion of sex steroid hormones
48
What does the increase in sex steroid hormones cause
1. Negative feed back loop
2. Inhibits responsiveness to GnRH
3. Inhibits secretion of GnRH
49
What is stress
Real or percieved threat to homeostasis
50
What is Cortisol and where is it produced
Glucocorticoid
Secreted by the adrenal cortex
51
What does cortisol do on the body
Increases blood sugar level
| Decreased immune response
52
What is Epinephrine and where is it produced
Catecholamine
Secreted by the adrenal medulla
53
What does epinephrine do on the body
Fight or flight
Increases heart rate
Increases respiratory rate
Shifts blood to skeletal muscles
54
What does the adrenal medulla secrete
Catecholamines
| E and NE
55
What does the adrenal cortex secrete
Corticosteroids
| Adrenal androgens
56
What are the 4 main functions of cortisol
1. Maintenance of normal blood pressure
2. Maintenance of cellular concentration of enzymes
3. Anti - inflammatory and anti immune functions to control overactive immune system
4. Differentiation of tissues and glands in fetal and neonatal stages
57
Steps of the pituitary-adrenal axis
1. Stress increases secretion of corticotropin releasing hormone (CRH) from hypothalamus
2. Secretion of ACTH by anterior pituitary
3. Secretion of cortisol by adrenal cortex
4. Negative feedback
58
What is adrenal insufficiency known as
What causes it
What are the effects of it
Addisons disease
Low plasma cortisol level
Weakness, decreased BP, dehydration
Anterior pituitary tumor
59
What is Cushings syndrome
What causes it
What are the effects of it
High plasma cortisol level
ACTH secreting tumor, adrenal tumor, long term steroid use
Diabetes like symptoms, high BP, immunosuppression
60
What does the thyroid gland do
Controls metabolic rate
On the esophagus below larynx - has two lobes
61
What are thyroid follicles lined with
Follicular cells that synthesise thyroxine
62
What 2 hormones are produced in the thyroid gland that contain iodide
Triiodothryonine (t3)
| Thyroxine (T4)
63
Explain the steps of synthesising thyroid hormone (7)
1. Iodide (I-) from ISF enters colloid - oxidised and attaches to thyroglobulin protein
2. Enzymes change the structure of MIT and DIT and couple them
3. T3 is produced from one MIT attaching to one DIT
4. T4 is produced from two DIT coupled
5. Pinocytosis of T3 and T4 into follicular cells
6. T3 and T4 released from Thyroglobulin
7. T3 and T4 secreted by diffusion into ISF
64
What is TSH, where is it produced and what does it do
Thyroid stimulating hormone
From anterior pituitary
Stimulates follicle activity and growth of thyroid
65
What stimulates TSH to be secreted and where is it produced
TRH - Thyrotropin releasing hormone
| Produced by hypothalamus
66
What is the 3 basic hormone sequence with thyroid
TRH (hypothalamus)
TSH (Anterior Pituitary)
T3/T4 (Thyroid gland)
67
What do thyroid hormones do on the body
1. Stimulate carbohydrate absorption from small intestines
2. Increase fatty acid release
3. Calorigenic action = temp for homeostasis
4. Effects on catecholamines
68
What is hypothyroidism
Lower than normal plasma concentration of thyroid hormones
69
Where would be the primary defect
Secondary defect
Tertiary defect
```
Primary = thyroid gland
Secondary = Anterior Pituitary
Tertiary = Hypothalamus
```
70
What mineral do people lack worldwide
| What cause does it have on the system
Iodine deficiency
Decrease T3/T4
Reduced negative feedback on pituitary
Increase TRH and TSH
71
What is the appearance of someone with hypothyroidism
Enlarged thyroid / goiter
Due to overstimulation of gland/ production of T3/T4
72
What is Hyperthyroidism
Higher than normal plasma concentration of thyroid hormones
73
What causes hyperthyroidism
Graves disease - activation of TSH receptors by antibodies
Hormone secreting tumors
74
What are the effects of hyperthyroidism
What does it cause on the body
TSH level low due to negative feedback
Excessive secretion of thyroid hormones
Causes:
heat intolerance
weight loss
Goiter = T3/T4 reduce TSH secretion
