Endocrine Physiology Flashcards
(39 cards)
1
Q
What are the major processes endocrine hormones regulate
A
Reproduction
Growth and development
Maintenance of homeostasis
Regulation of metabolism
2
Q
How do endocrine “gland” sense and signal
A
- Endocrine glands synthesize and store hormones
- Glands have sensing and signaling system to regulate duration and magnitude of hormone release via feedback from target cell
3
Q
What are the 7 main endocrine glands
A
- Hypothalamus
- Pituitary gland
- Pineal gland
- Parathyroid glands
- Thyroid gland
- Adrenal glands
- Pancreas
4
Q
What are the 6 organs with secondary endocrine functions
A
- Heart
- Thymus
- Adipose
- Digestive tract
- Kidneys
- Gonads
5
Q
Hypothalamus secretes
A
- Antidiuretic hormone
- Oxytocin
- Regulatory hormones
6
Q
Pineal gland secretes
A
Melatonin
7
Q
Parathyroid glands secrete
A
Parathyroid hormone
8
Q
Thyroid releases
A
- Thyroxine (T4)
- Triiodothyronine (T3)
- Calcitonin
9
Q
Adrenal cortex releases
A
- Cortisol, corticosterone, aldosterone, androgens
10
Q
What are the 2 types of local hormones
A
- Paracrine act on neighboring cells
- Autocrine act on themselves
11
Q
Hormones general functions
A
- Stimulate synthesis of enzymes or structural proteins
- Increase or decrease rate of synhesis
- Turn existing enzymes or membrane channels on or off
12
Q
What are the 3 classes of hormones
A
Amino acid derivatives
Peptide hormones
Lipid derivatives
13
Q
Amino acid derivatives
A
- small structurally related to AA
- Derivatives of tyrosine
- Thyroid hormones
- Catecholamines
- Epinephrine, norepinephrine, dopamine
- Derivatives of tryptophan
- Serotonin and melatonin
14
Q
Peptide hormones
A
- Chains of AA
- Most are made as pro-hormones
- Inactive molecules converted to active before or after secreted
15
Q
Glycoproteins
A
- Are peptide hormones
- More than 200 AA with carbohydrate side chains
- Thyroid stimulating hormone
- Luteinizing hormone
- Follicle-stimulating hormone
16
Q
Short polypetides/Small proteins
Peptide hormones
A
- Includes all hormones secreted by
- Hypothalamus
- Heart
- Thymus
- Digestive tract
- Pancreas
- Posterior pituitary
17
Q
Short chain polypeptides
ex
A
Antidiuretic hormone
Oxytocin
18
Q
Small proteins
ex
A
Growth hormone
Prolactin
19
Q
Lipid derivatives
Eicosanoids
ex and functions
A
- Derived from arachidonic acid, a 20 carbon fatty acid
- Paracrine factors coordinate cell activities and effect enzymatic processes in extracell fluids (blood clotting)
- Some eicosanoids like leukotrienes have secondary roles
20
Q
Prostaglandins
A
- Lipid derivative, eicosanoids
- Coordinate cell activities
- In some tissues prostaglandins are converted to thromboxanes and prostacyclins
- have strong paracrine effects
21
Q
Steroid hormones
released by
A
- Reproductive organs- androgens (testes) estrogens and progestins by ovaries
- Adrenal cortex
- Corticosteroids
- Kidneys
- Calcitriol
22
Q
How are steroid hormones transported in plasma
A
Steroid hormones are bound to specific transport proteins in plasma
Remain in circulation longer than peptide hormones
23
Q
Free hormones
Last for
how are they broken down
A
- Remain functional for less than an hour
- Diffuse out of blood stream and bind to receptors
- Broken down and absorbed by liver and kidney
- Broken down by enzymes in plasma or interstitial fluid
24
Q
Thyroid and steroid hormones circulation
A
- Remain in circulation longer bc bound
- Enter blood stream and most will become attached to secial transport proteins
- Blood stream has substantial reserve of bound hormones
25
Catecholamines and peptide hormones
entrance to cell
* Are not lipid soluble
* Must bind to an extracellular receptor
26
Eicosanoids
Entrance to cell
Are lipid soluble
Diffuse across plasma membrane and bind intracellular receptors
27
First and second messengers general
* Bind to receptors in plasma membrane
* Cannot have direct effect on activities inside target cell
* Use intracellular intermediary to exert effects
28
First messenger action
Leads to second messenger
May act as enzyme activator, inhibitor, cofactor
Results in change in rates of metabolic reactions
29
Second messengers action and some imp examples
* Mediate intracellular hormonal functions
* Imp second messengers
* Cyclic-AMP (cAMP)
* Derivative of ATP
* Cyclic-GMP (cGMP)
* Derivative of GTP
* Calcium ions
30
Down and up regulation btw hormones and receptors
* Down regulation
* Prescence of hormone triggers decrease in number of hormone receptors
* When hormone levels are high, receptor is less sensitive
* Up regulation
* Absence of ormone triggers increase in receptors
* When hormone levels are low, cells become more sensitive
31
Affect of hormones acting on intracellular receptors
type of hormones that do this
* Alter rate of DNA transcription in nucleus, protein synthesis
* Affect metabolic activity and structure
* Include steroid and thyroid hormones
32
Endocrine reflex and control of it
* Functional counterpart of neural reflexes
* In most cases controlled by negative feedback
* A stimulus will trigger production of hormone
* The hormones direct or indirect effects then reduce the intensity of the stimulus
33
What can trigger endocrine reflexes
* Humoral stimuli
* Changes in composition of extracellular fluid
* Hormonal stimuli
* Arrival or removal of hormone
* Neural stimuli
* Arrival of neurotransmitters at neuroglandular junctions
34
Simple endocrine reflex
* Involves 1 hormone
* Controls hormone secretion by
* Heart
* Pancreas
* Parathyroid
* Digestive tract
35
Complex endocrine reflex
* 1 or more intermediary steps
* 2 or more hormones
36
Antagonistic
Actions oppose eachother
37
Synergistic
Actions ENHANCE effects of each other
38
Permissive
Effects ocur when 1 hormone is required for the other to function
39
Integrative
Effects occur when the hormone action differs with differing target organs
