Week 6-7 - Study Guide - Part 3 Flashcards
Where is the Thyroid gland located/
In the throat area in the front of the neck
What is the Isthmus?
The Isthmus connects the two lobes of the thyroid gland
What two hormones does the Thyroid gland produce?
- Thyroid Hormone
- Calcitonin
Which hormone of the thyroid is a major metabolic regulator?
Thyroid Hormone
Which hormone of the thyroid is all about Calcium concentration?
Calcitonin
Where is the parathyroid gland?
On the backside of the thyroid gland, the little yellow glands.
People can have anywhere from 4-8
What hormone does the parathyroid gland produce?
Parathyroid hormone
What does the parathyroid hormone release?
Calcium concentration regulation
Releases Calcium ions when low
What are the structures you can see on the thyroid?
Follicles
Open spaces that create a lot of glycoproteins called thyroglobulin
A fancy way of saying they do protein synthesis.
What do you add to thyroglobulin to create a thyroid hormone precursor?
Iodine
What are the two things needed to stick together to make thyroid hormone?
Thyroglobulin and iodine
What fills all the open spaces in the follicle on the thyroid gland?
Thyroid hormone
What are the cells that produce calcitonin and are directly associated with the open spaces on the thyroid?
Parafollicular cells (little cells)
What hormone is used to store calcium when too high?
Calcitonin
What hormone is used to release calcium when low?
Parathyroid hormone
Thyroid Hormone has two related compounds…
T4
T3
What is the difference between T3 and T4?
Amino acid based
mix of tyrosines and iodine atoms
~T3 - has 3 bound iodine atoms
10x more metabolically active than T4
~T4- has 4 bound iodine atoms
it gets converted at the target tissue to T3 by peripheral tissue enzymes
What does the Thyroid hormone do?
- Metabolic Regulator
the more you have the higher the metabolic rate - Regulates growth and development of tissues
(especially in the nervous tissue)
Involves negative feedback
Without the thyroid hormone what happens to the nervous system and body tissues?
The nervous system does not develop
many of the body’s tissues will not develop properly
No metabolism stimulation
What regulates Thyroid hormone and its release?
Hypothalamus
Thyroid Hormone Effects -
(Maintain normal metabolism)
- Increases metabolism
- Regulates tissue growth & development (especially in the nervous system tissue)
- Increases reactivity of nerve cells
(heart rate & digestive motility)
Autonomic Nervous System Regulation
If you need metabolism to run you need digestion
Thyroid System
- Hypothalamus releases TRH
- THR (Thyrotropin-releasing hormone) goes to the anterior pituitary
- Anterior pituitary - causes the release of TSH (Thyroid-stimulating hormone)
- goes to the thyroid gland
- where T3 and T4 are being produced
- then goes out to various target organs all over the body -
for growth and development
increase action of all those tissues
Negative Feedback
1. If you have enough T3 & T4 you will slow down the secretion of TSH and TRP
What do you need from the diet for the Thyroid?
Iodine
T3
10x more metabolically active than T4
T4
converted to T3 by peripheral tissue enzymes
Hyposecretion of Thyroid hormone in adults due to lack of iodine?
Endemic Goiter
Need iodine to complete thyroglobulin to make thyroid hormone.
Without iodine, Thyroid gland continues to make more and more thyroglobulin
BUT - cannot finish any of it so thyroglobulin continues to build up.
You never have T3 and T4
You never get negative feedback to the anterior pituitary or hypothalamus
SO- you get those goiters
Differences between the two dwarfisms.
Pituitary and Cretinism
Pituitary Dwarfism -
nothing wrong - Low Growth Hormone ONLY makes person very small
Cretinism Dwarfism -
stuff wrong with them
Hyposecretion of Thyroid hormone in adults results in
Myxedema
(Mucous swelling)
Myxedema is a hyposecretion in adults resulting in s/s:
- lethargy (w/o metabolism - slowing down)
- Low body Temperature (because the heat producer is metabolism. Metabolism is not happening so results in low temp
- Swollen Face
- Edema (swelling- build up around the eyes)(more common in older people)
- Leathery skin (changes the skin of the face - associated with vascular)
- mental sluggishness
- Thick dry skin (change in skin consistencies)
Disease associated with Hypersecretion of Thyroid Hormone in Adults.
Graves’ Disease
More in adults but could happen in kids
Graves’ disease is a hypersecretion in adults resulting in s/s:
Actor Marty Thelman
- High metabolic rate
- Exopthalamia (bulging of the eyes due to build-up of fluid that pushes the eyes out of the socket
- WBC accumulation enlarges CT & muscles
- weight loss
- excessive sweating
- anxiety
- heart rate
Antibodies mimic TSH…so what happens?
Autoimmunity exposed to something
If antibody is too close - it will go after the substance that is similar
Hyposecretion of (TH) Thyroid hormone in infants causes what condition?
Cretinism (dwarfism)
Cretinism is a hyposecretion in children resulting in s/s:
- Small limbs
- Not good Nervous System development
- Developmental may stem from low thyroid hormone in both mother and infant
- Small stature (low metabolism)
- mental retardation (not developing appropriately)
- Low body temperature (due to low metabolism)
Fat build
POMC - Origin of
Origin of
1. ACTH
2. MSH
3. Endorphins
4. Enkephalins
Releasing Hormones
From the True Master Gland -
the hypothalamus!!
ACTH
LH
FSH
TSH
Tropic hormones
known for release of other hormones
Adenohypophysis VS Neurohypophyis
Adenohypophyis -
1. Adeno - true gland - anterior pituitary gland
2. produces own hormones
Neurohypophyisi -
1. Neuro - posterior pituitary
2. made in hypothalamus –> into posterior pituitary –>NS causes release
Portal Systems
- Specialized vascular organization with 2 capillary beds in a row to pickup substances from 1st and deliver them to the 2nd.
EX - Cardiovascular specializations
T3 vs T4
T3 - 10x more metabolically active
T4 -converts to T3 at target cells
2 types of dwarfism
- Pituitary dwarfism - due to lack of GH
- Cretinism - lack of TH and associated with cognitive impairment
Steroid vs. Amino-acid-based
Steroid - Lipid
1. Slower
2. enters the cell and is slower
Amino-Acid-based - Protein
1. Faster
2. involves 2nd messenger systems
3. faster due to differences in chemistry of hormone and whether or not it can cross the cell membrane
Myxedema, Graves disease, goiter
Myxedema -
1. elderly
2. Low TH
3. mucous swelling
Graves’ disease
1. Hypothyroidism
2. Bulging eyes
3. High metabolism
Goiter
1. Lack of thyroid hormone
2. lack of iodine in diet
Homeostasis activity in Calcium increase in the blood
Osteoblast activity
Calcium ions uptake in bone
1.Calcium increase in blood - stimulant
2. Thyroid gland act as receptor and control center
3. Parafollicular cells of thyroid releasing calcitonin - the hormone that travels to the bone - specifically the osteoblast cells that become the effectors
4. Osteoblast become the effectors that cause the bone building
Absorb the calcium from the blood
Store it in the bone
Build up the ossification of the bone
Make it stronger
5. Blood calcium lower and returns to normal - homeostasis
1. Osteoblast activity
2. Calcium ions store in bone
Homeostasis activity in low calcium in the blood
Calcium ion absorption
Osteoclast activity
Calcium reabsorption
- Stimulant - low calcium in blood
- Thyroid gland act as receptor and control center
Parathyroid gland releases PTH
That travels through the blood
To the bone - osteoclasts (destruction) - PTH travels through the blood –>
To the bone –>
The osteoclasts
to increase the breakdown of bone
To let the calcium out to get released into the bloodstream
and calcium levels go up - Released calcium from the breaking down of bone and calcium in to the bloodstream
Causing the calcium levels to go back up
Can you live without Parathyroid Hormone?
No - you will die
Can you live withot Calcitonin
Yes
Hyperparathyroidism due to tumor
(breakdown of too much bone)
- causes the osteoblasts to break down the bone too much
- wind up with soft (brittle) bones that deform
- Start to bend under normal activity and forces
- More likely to have bone breaks
- Elevated Calcium depresses the NS and contributes to the formation of kidney stones
- Does NOT immediately kill you
Hypoparathyroidism
(associated with gland trauma or removal)
- At risk of DEATH
- Results in Tetany of the muscles (contract and do not let go)
- Respiratory paralysis (stop breathing)
- DEATH
Hypothyroid and swelling
Myxedema
Excess blood Calcium ions
Hyperparathyroidism
High heart rate, anxiety
Grave’s Disease
Lack of iodine in diet
Goiter
Cognitive deficit, dwarfism
Cretinism
Low GH, epiphyseal plate
Pituitary Dwarfism
Wasting and early aging
Simmond’s disease
Thickening of facial bones and hands
Acromegaly
Tetany, Respiratory paralysis
Hypoparathyroidism
High GH in childhood
Gigantism
Complexity of calcium regulations involves:
Increase in Calcium
1. Thyroid releases Calcitionin
2. increases calcium deposits in bone by osteoblasts
3. Decrease calcium uptake in intestines
4. Decrease calcium reabsorption from the urine
Decrease in Calcium
1. Parathyroid releases PTH
2. Increase calcium breakdown of bone by osteoclasts
3. increase calcium uptake in intestine
4. Increase calcium reabsorption from urine
Where are the Adrenal glands located?
sit on top of the kidneys
Structurally and functionally the adrenal glands are two glands in one:
- Adrenal Medulla
- Adrenal Cortex
Adrenal Medulla involves:
- Nervous Tissue
- part of the Sympathetic NS (F/F)
(NE, E)
Adrenal Cortex involves:
- glandular tissue that synthesizes & secretes 3 corticosteroids from 3 layers
- minerals
- nutrients/energy
- sexual
- glomerulosa
- fasciculata
- reticularis
Mineralocorticoids come from the outer regions of the
Adrenal Cortex
Aldosterone regulates…
Extra-Cellular-Fluid electrolytes
specifically - regulating Sodium and potassium
Extra Cellular Fluid is supposed to have a lot of sodium and a small amount of
Potassium
Aldosterone tries to keep it that way
Why is sodium so important?
- Amount of Sodium we have
- controls the amount of ECF volume we maintain
- which means we will have the right amount of BP, BV, and impacts the relative concentration of other ions
Sodium influx affects –
- ECF volume
- BV
- BP
- other ions
Sodium Efflux affects
- sets the resting membrane potential of the cells
- Having excess potassium changes the RMP of the cell
Aldosterone helps get rid of excesses
Kidney releases…to get to…
All goes to the same place
- kidney releases Renin –>
- Angiotensin –>
- to get here - Aldosterone
ACE is….
Inhibitor
have an issue already - stop making it worse
urinate it out
Renin causes a cascade of events in the plasma to produce a new chemical –
Angiotensin II
- which goes to the adrenal gland on top of the kidneys and causes release of
- Aldosterone
- which goes to the kidney
- Holds onto Sodium and water
- Causes the secretion of potassium
Impact of Renin is the same as
Angiostensin
which is the same as aldosterone
A cascade of events that all lead to aldosterone.
Renin leads to
Aldosterone
Angiotensin leads to
Aldosterone
Retain Na+ and H2O and secrete K+
Aldosterone production
