The Endocrine system: Organization and Acute/Chronic Response to Exercise Flashcards
(129 cards)
1
Q
What does the endocrine system consist of? Describe the role of endocrine glands
A
Endocrine system consists of HOST organ, minute quantities of Chemical messengers and Target or Receptor organ (messages are sent from host to target organ)
- Endocrine glands have NO DUCTS and SECRETE substances directly into extracellular spaces around the gland
- they require a bloodstream
2
Q
What is common feature for exocrine glands and where can they be seen in the body?
A
Exocrine glands- HAVE DUCTs and can be seen in digestive tract, within walls of GI tract, stomach and intestines
3
Q
What are the major endocrine organs?
A
Major endocrine organs:
- Pituitary
- Parathyroid
- Adrenal
- Pineal
- Thymus glands
4
Q
Also discuss other organs in the body that contain endocrine tissue.
A
Other organs that contain areas of endocrine tissue are Pancreas, gonads (ovaries and testes), hypothalamus, and Adipose tissues
5
Q
Describe the function of the neuroendocrine system
A
Neuroendocirne system- Regulate and integrate body functions using hormones
6
Q
What are hormones?
A
Hormones- Highly specialized organic molecules produced by Endocrine organs that regulates the function of specific target cells.
7
Q
Differentiate between the types of local signaling and long-distance signaling
A
Local signaling; signals that act locally between cells close together
1. Paracrine and Autocrine
-paracrine signaling: cell produces signal to induce changes in NEARBY cells (local regulator diffuses across interstitial fluid)
-Autocrine signaling: a cells secretes hormones that bind to autocrine receptor of the same cell (secreting cell)
2. Neurtotanmission (Nerve system) - signaling molecules called NEUROTRANSMITTER are released by axon terminal of a neuron (presynaptic) and bind to receptor on another neuron (post-synaptic)
-neurotransmitter molecules diffuse across synapse
Long Distance signaling-
1. Endocrine signaling- signals (hormones) are produced by specialized endocrine cells and released into BLOODSTREAM, which carries them to target cells in distant parts of body
- Neurosecretory- neural signals produced by neurosecretory cell, relesed in blood stream to send to target cells in distant parts of body
8
Q
What are the main categories of hormones and describe the different roles of hormones
A
Hormones are chemical substances synthesized by SPECIFIC host glands
Categories of Hormones:
-Steroid-derived hormones
-Amine and Polypeptide hormones
Most hormones circulate in the BLOOD as messengers that affect tissues a distance from the specific gland and others that exert LOCAL effects in their region of synthesis.
9
Q
What is half-life?
A
Half-life- the time required to REDUCE a blood hormone’s concentration by one half and gives us an indication of how long its effects Persists
10
Q
Describe the three major type of molecules that hormones can be.
A
Hormones can be:
- Amines and amino acids
- Peptides, polypeptides, proteins and glycoproteins
- Steroids
11
Q
Differentiate between water soluble and water insoluble hormones
A
Water soluble hormones- circulate FREELY in BLOOD (need a carrier get across membrane)
Water-insoluble hormones- requires a CARRIER to enter Blood (can easily move across membrane)
12
Q
Explain how water-insoluble and water soluble hormones enter the cell membrane
A
Water Soluble Hormones binds to cell-membrane RECEPTOR and activates signaling molecules (G-protein, adenyl cyclase-effector, cyclic AMP) to diffuse across membrane
Water insoluble hormones- diffuses across the cell membrane (easily) and binds to an activates an INTRACELLULAR receptor- translocates to the nucleus
-Affects GENE TRANSCRIPTION.
13
Q
What are the main hormones under Amine hormones ?
A
Amine Hormones: Catecholamines (epinephrine, norepinephrine) and Thyroid hormones (thyroxine, T4 and T3)
14
Q
Describe which of the form main categories are similar and its common features
A
peptide and Catecholamines (amine) are Most similar as they both have SHORT half life, dissolved in plasma. and activate second messenger systems, modify existing proteins made in advance, secretory vesicles
STEROID hormones and THYROID hormones are very similar and have common features like LONG lifespan ( half life), induction of new protein synthesis, activate genes for transcription and translation, bound to carrier proteins for transport, released from parent cell through simple diffusion and made from précursors
15
Q
which hormones are peptide hormones,?
A
Peptide hormones- Insulin, glucagon, Leptin, IGF-1
16
Q
which hormones are steroid hormones?
A
Steroid hormones: Androgens, DHEA, Cortisol
17
Q
Which hormones are Amine hormones (catecholamines, and Thyroxine (T4) )?
A
Amine hormones:
Catecholamines: Epinephrine/Norepinephrine
Thyroid Hormones:
Thyroxine (T4), and Triiodothyrodine (T3)
18
Q
What organ produces atrial natriuretic hormone and what stimulates its production. what is this hormone’s function?
A
Atrium of the heart produces atrial natriuretic hormones. This hormones is produced by stimulus of Atrial stretching.
The hormone will target kidneys and inhabit Na+ reabsorption and renin release
it will also target Adrenal Cortex and inhibit secretion of aldosterone
19
Q
Explain the ways in which hormones can alter cellular reactions of target cells
A
Hormones can alter cellular reactions of specific target cells by:
- Modifying the rate of intracellular protein synthesis by stimulating nuclear DNA
- Changing rate of Enzyme activity
- Altering Plasma membrane transport via second-messenger system.
- Inducing secretory activity
20
Q
Why is hormone receptor binding important. What determines a hormone’s ability to activate target cell?
A
Hormone-receptor binding (hormone bind to receptor) is FIRST Step in INITIATING hormone action
- The extent of a target cell’s activation by a hormone depends on:
- Hormone concentration in the blood
- The number of target cell receptors for the hormone
- Sensitivity or strength of the union between the hormone and receptor
21
Q
Describe the action of non-steroid hormones. Provide examples of non-steroid hormones.
A
Non-steroid hormones (like Epinephrine and glucagon) will have downstream pathway of hormone binding to specific receptor, activating adenylate cyclase, and the adenylate cyclase activates Cyclic AMP and Protein kinase= active protein kinase which will allow active target enzyme to induce cellular response.
22
Q
Explain the hormone effects on enzymes. How can a hormone increase enzyme activity?
A
Major hormone actions include altering enzyme activity and enzyme-mediated membrane transport
A hormone can increase enzyme activity by:
-Stimulating enzyme production
-Combining with the enzyme to alter its shape and ability to act, which increases or decreases the enzyme’s catalytic effectiveness
-Activating Inactive enzyme forms, thus increasing the total amount of active enzyme
23
Q
Explain the importance of adjusting hormone secretion. What factors determine plasma concentration of hormones?
A
Hormone secretion usually adjusts rapidly to meet the demands of changing bodily conditions
Factors that determine plasma concentration of particular hormone:
-Quantity of hormone synthesized in host gland
-Rate of either catabolism (breakdown) or secretion into blood
-quantity of transport proteins present
-Plasma volume changes
(if decrease plasma volume, increase plasma concentration)
24
Q
explain how secretion determines plasma concentration of hormone. what else besides secretion determines plasma concentration of hormone?
A
Secreted amount of hormone describes the plasma concentration and represents SUM of HORMONE Synthesis and release by the host gland; in addition to its uptake by receptor tissues and removal by liver and kidneys.
CHANGES in PLASMA VOLUME also alter hormone concentrations, independent of host organ’s secretion rate.
25
What are three main types of stimulation factors for endocrine gland activity ?
Endocrine Gland Activity stimulation factors:
- HORMONAL stimulation: Hormones influence secretion of other hormones
- HUMORAL stimulation; Changing levels of ions, and nutrients in blood, bile, and other body fluids stimulate Hormone release
- NEURAL stimulation- neural activity affects hormone release
26
Explain major examples of the stimulation factors for endocrine gland activity.
Endocrine gland stimulation:
- Hormonal stimulation:
- 1. ACTH from anterior pituitary is released into blood
2. This stimulates adrenal cortex to secrete glucocorticoids
3. Glucocorticoids influence several target organs
4. glucocorticoids exert negative feedback on ACTH release
- Humoral stimulation:
1. Capillary blood containing high concentration of glucose
2. This will cause INSULIN to be secreted by pancreas (enter blood)
3. Target cells will absorb more glucose from blood
4. have Capillary blood in which glucose levels have dropped
5. Low blood sugar levels inhibit insulin release
- Neural Stimulation:
1. Preganglionic sympathetic nerve fiber stimulates Adrenal Medullary cells
2. Adrenal medullary cells secrete CATECHOLAMINES into blood
27
Describe the pattern of hormone release and why it is important . What is the most common pattern?
Patterns of hormone release:
-Most hormones respond to PERIPHERAL STIMULI on an as-needed basis
-Some hormones release at regular intervals during a 24-hour cycle in a diurnal pattern or cycle of secretion
-Some secretory cycles span several weeks while others follow daily cycles
Ex: sleep cycle or women's monthly period
Patterns of release and or Amplitude and Frequency of discharge provide MORE information on HORMONE DYNAMICS than simply examining mean concentration at any single time.
28
Describe where anterior pituitary is located and how many hormones it secretes. Also discuss what organ controls anterior pituitary activity and the additional thing primary pituitary hormones have and what controls them.
Anterior pituitary is located beneath the Base of the brain and Secretes SIX specialized polypeptide hormones (FLATPIG)
-The HYPOTHALAMUS controls the Anterior pituitary activity
-Each of the primary pituitary hormones has its own hypothalamic RELEASING Hormone called Releasing Factor
-NEURAL Input to Hypothalamus from Anxiety, stress and physical activity controls output of these Releasing factors.
-
29
What are the hormones located in the anterior pituitary?
```
Hormones in Anterior pituitary:
FSH- Follicle stimulating hormone
LH- Lutenizing hormone
ACTH- Adrenocorticotropic hormone
TSH- Thyroid stimulating hormone
Prolactin
Growth Hormone
```
30
List the main hormones that are located in the anterior pituitary and the target cells they stimulate.
Anterior pituitary:
Lactogen (prolactin) -stimulates the breast
Gonadotropic hormones (FSH, LH) that stimulate the ovaries and testes (produce estrogen, progesterone, and testosterone)
-ACTH (corticotropin) stimulates the adrenal cortex (which produces cortisol, aldosterone)
-Thyrotropin stimulates the thyroid which produces thyroxine (T4) and Triiodothyroinine (T3)
-Growth hormone (somatotropin) stimulates many organs
-Endorphins - stimulate diverse organs and tissues
31
What is the role of hypophysis?
Hypophysis- Portal system (connection) between the hypothalamus and pituitary
-it controls several endocrine glands and many physiological functions
32
What is the role of hypothalamus?
Hypothalamus- control center for the endocrine system- where Neural input (emotion, pain, body temp) and immune and inflammatory responses (CYTOKINES) are communicated to the endocrine system.
33
How are most pituitary hormones regulated?
Most pituitary hormones are regulated by HYPOTHALAMIC Stimulating Hormones via Hypophyseal portal system.
34
What is the pituitary gland also called? List the five types of cells in anterior pituitary gland
Pituitary gland aka MASTER Gland
5 types of cell in Anterior Pituitary Gland:
1. Somatotrophs- human growth hormone (hGH) (somatropin)
2. Thyrotrophs- Thyroid-Stimulating hormone
3. Gonadotrophs- Follicle stimulating hormone (FSH) and Lutenizing Hormone (LH) (gonadotropins)
4.Lactotrophs- prolactin (PRL)
5. Corticotrophs -adrenocroticotropic hormone (ACTH) (corticotropin)
35
Explain the role of Growth hormone in the body. Also include the ways that Growth Hormone facilitates protein synthesis in adults. How does it relate to carbohydrates?
Growth hormone promotes CELL DIVISION and CELLULAR PROLIFERATION
-In adults, Growth Hormone facilitates protein synthesis by:
1. increasing amino acid transport through the plasma membrane
2. Stimulating RNA formation
3. Activating cellular ribosomes that increase protein synthesis
Growth hormone also SLOWS Carbohydrate Breakdown and INITIATES subsequent Mobilization an use of FATS as an Energy source
36
What is the most plentiful anterior pituitary hormone?
HUMAN GROWTH HORMONE (hGH)
37
What is the main function of human growth hormone (hGH)?
Function of human growth hormone (hGH)- promote SYNTHESIS and SECRETION of INSULIN-like Growth Factors (IGFs) (somatomedins) by liver, skeletal muscle, cartilage, and bone cells
38
Describe the major roles of Insulin Growth Factors (IGFs)
Insulin Growth Factors (IGFs):
1. ACCELERATE protein synthesis (increase cellular uptake of amino acids, INHIBIT breakdown of amino acids, inhibit Amino acid use in ATP production
2. ENHANCE lipolysis in Adipose tissue- Release fatty acids for use in ATP production
3. DECREASES use of glucose for ATP production in most body cells- available glucose is able to be used by neurons in times of glucose scarcity
39
Differentiate between the induction and inhibition of growth hormone. Does growth hormone undergo Negative feedback?
Induction- Growth Hormone-releasing hormone; GHRH (increasing activity of GH)
Inhibition- Growth hormone- inhibiting hormone; GHIH (decreases activity of GH)
GHIH (aka somatostatin)
40
Describe how physical activity affects Growth hormone and tissues in the body.
Physical activity EXTENDS GH's (growth hormone) action on target tissues
- Benefits muscle, bone, and connective tissue Growth and Remodeling
- Optimizes the FUEL mixture during physical activity
- The net metabolic effect preserves plasma glucose concentration for Central nervous system and muscle functions
41
Compare and contrast Growth hormone level changes in trained and sedentary individuals. Which individual has higher GH levels during recovery?
Trained and sedentary individuals show similar INCREASES in GH Concentration with Exercise to Exhaustion, But SEDENTARY person maintains HIGHER GH levels for several hours into recovery.
Since sedentary can have higher gains, they have better way of improvement during exercise (so you want to spare glucose and use fat for fuel)
42
Describe the feedback control that occur in hypothalamus with growth hormone releasing and inhibiting hormone and its effects on target cells.
Hypothalamus secretes GHRH, GHIH, or somatostatin
Feedback control: can inhibit GHRH release and stimulate GHIH release from hypothalamus; which can further inhibit GH synthesis and release by Anterior pituitary
43
What are the direction and indirect actions for growth hormone? Be sure to include the effects on target cells.
Growth Hormone
Direct actions (anti-insulin):
-stimulate Triacyclgylerol release in Adipose tissue
-Hinders glucose uptake to maintain blood sugar level
Indirect actions (promote anabolism)
-Liver and other organs will stimulate somatomedins (IGFs):
Nonskeletal effects: increases synthesis of protein and new cell growth
Skeletal effects- increases formation of cartilage and promotes skeletal growth.
44
Explain how IGFs and Growth hormone relates. what do liver cells secrete due to GH stimulation? Discuss how IGF's interact with receptors.
IGFs MEDIATE many of Growth hormone's effects
-In response to GH stimulation, liver cells synthesize IGF-I and IGF-II
IGFs travel in the blood Attached to one of the five types of Binding proteins for release as FREE hormones to interact with SPECIFIC receptors
45
List the major factors that stimulate IGF (insulin like growth factors) Transport
Factors that influence IGF transport:
- Binding proteins within muscle
- Nutritional status
- Plasma insulin levels
46
Explain the role of ACTH and describe which system it is part of.
ACTH (adrenocorticotropic hormone) functions as part of Hypothalamic-Pituitary -Adrenal axis to Regulate adrenal cortex output of hormones
-ACTH acts directly to ENHANCE fatty acid mobilization from adipose tissue, INCREASE Gluconeogenesis, and STIMULATE protein catabolism.
47
Which molecules mediate ACTH release? Also what kind of actions favor the release of these mediators, that will induce ACTH.
Corticotropin Releasing Hormone (CRH) and Arginine VASOPRESSIN (AVP) Mediate ACTH release
-HIGH-INTENSITY Physical activity Favors AVP (vasopressin) release, while PROLONGED physical activity favors CRH release which both induces ACTH.
48
Describe the major function of ACTH and what occurs during induction and inhibition (including the molecules involved)
ACTH (adrenocorticotropic hormone) ACTH
Function: Controls the Production and Secretion of Cortisol other glucocorticoids by the adrenal gland.
Induction: Corticotropin-releasing hormone (CRH): Stress related stimuli (low blood glucose or physical trauma); interleukin-1 (macrophages)( increases release of ACTH)
Inhibition: Glucocorticoids INHIBIT CRH and ACTH.
49
Explain the role of thyrotropin, and also what is another name for this molecule?
Thyrotropin, aka THYROID-STIMULATING HORMONE (TSH) controls hormone secretion by the thyroid gland.
-TSH maintains GROWTH and DEVELOPMENT of Thyroid gland and Increases Thyroid Cell metabolism.
50
Describe the major function of TSH and the molecules that induce and inhibit it.
TSH (thyroid-stimulating hormone)-
Function: stimulates Synthesis and Secretion of triiodothyronine (T3) & thyroxine (T4) form the thyroid gland
Induced: thyrotropin-releasing hormone (TRH)
Inhibition: HIGH levels of T3 and T4 INHIBIT TRH (NEGATIVE FEEDBACK)
51
What are the main hormones in the posterior pituitary and what are their functions. Also discuss how physical activity affects these hormones
Posterior pituitary hormones: ADH (vasopressin) and OXYTOCIN (stored hormones)
- ADH Influences Water Excretion by Kidneys (helps preserve water)
- Oxytocin INITATES Muscle contraction in Uterus and Stimulates Ejection of milk during Lactation
- Physical activity provides a potent STIMULUS for ADH secretion to help conserve body fluids
- The effect of short-term physical activity on oxytocin release remains UNKNOWN.
52
Explain what makes the posterior pituitary unique when it comes to its hormones.
The posterior pituitary does NOT synthesize hormones; they STORE and RELEASE hormones (oxytocin and ADH) via NEUROSECRETORY cells (cell bodies in hypothalamus)
areas in hypothalamus make the hormones
53
What part of the Hypothalamus synthesizes oxytocin and describe the role and function of this hormone during and after delivery
The PARAVENTRICULAR NUCLEUS in the hypothalamus synthesizes oxytocin.
During Delivery of baby- Oxytocin Enhances CONTRACTION of smooth muscle cells in the wall of the Uterus
After Delivery- Oxytocin stimulates MILK EJECTION (letdown) in response to infant suckling
54
What part of the hypothalamus produces ADH (vasopressin) and what are the major functions of this hormone?
Which molecules induce and inhibit ADH?
The SUPRAOPTIC NUCLEUS- produces Antidiuretic hormone (ADH) or Vasopressin
ADH functions:
-Decrease Urine production
-Causes kidneys to Return more water to the blood
-Induces SWEATING and Constriction of arterioles (INCREASES blood pressure)
- Induction: Blood OSMOTIC Pressure and Blood volume
Inhibition: Alcohol inhibits ADH
55
What are the major thyroid hormones. Describe their individuals functions as well as general functions and roles of thyroid hormones
Thyroid hormones are Thyroxine (T4) and Triiodothyroinine (T3)
-T4 secretion RAISES METABOLISM of all cells, except, brain, spleen, testes, uterus, and thyroid gland
-T3 release facilitates NEURAL REFLEX activity, whereas LOW T4 levels will cause SLUGGISHNESS
Thyroid hormones provide important regulation for Tissue Growth and Development, Skeletal and nervous system formation and Maturation and Reproduction
-They also play a role in Maintaining BLOOD PRESSURE by provoking an Increase in Adrenergic Receptors in blood vessels.
56
Describe where the thyroid is located, its structure and the main function
Thyroid- Located just inferior (below) the Larynx
Has Left and right lobes connected by ISTHMUS (butterfly shaped)
-Thyroid Produces and Secretes T3, T4, and Calcitonin in response to Thyroid stimulating hormone (TSH) (anterior pituitary)
57
What are thyroid follicles and what does their structure look like? Also discuss how follicular cells are affected by thyroid hormones, and also describe funciton of C cells.
Thyroid follicles- Microscopic Spherical sacs; their wall consists of follicular cells- basement membrane that surrounds each follicle (also colloid enclosing follicular cells)
-Follicular cells Change SHAPE when actively Secreting T3 and T4
Parafollicular cells (C cells)- Located Between follicles and Produce CALCITONIN
58
What molecule produces Calcitonin and what is the role of calcitonin?
```
Parafollicular cells (C cells) produce calcitonin
Calcitonin- helps regulate blood calcium (by inhibiting osteoclast activity that breaks down bone and releases Ca+ into blood
```
59
Explain the process of negative feedback that occurs with thyroid hormone release
Thyroid hormone release:
TSH from anterior pituitary will lead to secretion of thyrotropin.
This thyrotropin will lead to secretion of thyroxine(T4) and eventually an increased rate of cellular metabolism (by T4) will cause Inhibition of hypothalamic stimulation of anterior pituitary.
Negative feedback: High levels of T3, T4 will inhibit TSH from anterior pituitary
60
What kind of molecule are T3, and T4 (thyroid hormones) and what is needed to move across membrane and enter blood?
T3 and T4 are LIPID SOLUBLE- they can diffuse though the membrane (w/o carrier) into interstitial fluid and then the blood- by combining with TRANSPORT protein (thyroxine-binding globulin- TBG, Thyroxine-binding pre albumin-TBPA, or albumin)
T3 and T4 NEED a carrier to enter blood
and hence are Water Insoluble.
61
Describe the process of how T3 and T4 is made and enters bloodstream
Process of making T3, and T4:
1. Thyroglobulin is synthesized (In rough ER) and discharge into follicle lumen
2. Iodide (I-) is trapped (actively transported in)
3. Iodide is oxidized to IODINE
4. Iodine is attached to tyrosine in colloid, forming DIT and MIT
5. iodinated tyrosinase are linked tougher to form T3 and T4
6. Thyroglobulin colloid is Endocytosed and combined with lysosome
7. Lysosomal enzymes CLEAVE T4 and T3 from thyroglobulin and hormones diffuse into bloodstream.
62
Describe the effects of hyperthyroidism.
Thyroid hormones provide essential stimulation for normal growth and development
Hyperthyroidism (too much thyroid hormone) produce the following effects:
1. INCREASED Oxygen Consumption and Metabolic Heat production during rest
2. INCREASED Protein Catabolism and subsequent muscle Weakness and Weight loss
3. Heightened Reflex activity and psychological disturbances that range form irritability to insomnia to psychosis
-RAPID Heart Rate
63
What are the effects of hypothyroidism?
Hypothyroidism ( Low T3, T4) produces the following effects:
1. REDUCED metabolic rate and COLD-INTOLERANCE from Reduced internal heat production
2. DECREASED Protein synthesis produces brittle nails, thinning hair, dry, thin skin
3. Depressed Reflex Activity, SLOW SPEECH and thought processes, and Feeling of FATIGUE (sluggish)
2. SLOW heart rate.
64
Describe the major actions of Thyroid hormones
most cells have Receptors for T3 and T4
Actions of thyroid hormones:
1. Increase basic metabolic rate- increase the rate of oxygen consumption under "normal" conditions by inducing the use of O2 to produce ATP (increases the metabolism of carbohydrates, lipids and proteins)
2. Calorigenic effect- stimulate the synthesis of Na+/K+ Atpase -cells produce and use more ATP- body temperature rises -maintenance of normal body temperature.
3. Increase the use of glucose and fatty acids for ATP synthesis- stimulates protein synthesis- increases lipolysis and enhances cholesterol excretion
4. Enhance Catecholamine action- up regulate Beta-receptors for Norepinephrine and Epinephrine (heart rate, blood pressure increase
5. Growth and development- together with hGH and Insulin, Accelerate body growth (nervous and skeletal system)
6. Nervous System- too much induces Anxiety and Nervousness; too little results mental sluggishness.
65
Describe the process of controlling thyroid hormone secretion
Control of thyroid hormone secretion:
1. LOW blood levels of T3 and T4, conditions that increase ATP demand ;or Low metabolic rate stimulates HYPOTHALAMUS to secrete TRH
2. TRH enters the hypophyseal portal veins and flows to the anterior pituitary- stimulates thyrotrophs to SECRETE TSH.
3. TSH enters systemic circulation and induces follicular cells- iodide trapping, hormone synthesis and secretion and growth of follicular cells.
4. Follicular cells Release T3 and T4 into the blood stream (bind to carrier- TBG, TBPA, or albumin)
5. Elevated levels of T3 INHIBIT release of TRH and TSH (Negative Feedback Inhibition)
66
Where are parathyroid glands located and what is there structure like?
Parathyroid glands- Several small, Round masses of tissue partially embedded In POSTERIOR surface of the lateral lobes of the thyroid
There are FOUR lobes: one superior, and one inferior per lateral lobe
67
what are the two types of epithelial cells for parathyroid glands?
Two types of epithelial cells:
- Chief (principal) cells- produce parathyroid hormone (PTH)
- Oxyphil cells- Function UNKNOWN
68
Describe the functional role of parathyroid hormone (PTH). discuss what influences changes in PTH release
Parathyroid hormone controls CALCIUM BALANCE
-A Decrease in Calcium levels Triggers PTH release
Increasing Calcium concentrations INHIBIT PTH Release
69
What are major effects of PTH (parathyroid) release ?
PTH release results in following effects:
- Activation of OSTEOCLASTS to Digest the bone matrix to release Ionic Calcium and Phosphate to the blood
- Enhancement of Calcium ion reabsorption and DECREASED retention of phosphate by kidneys
- Increased Calcium absorbed by Intestinal mucosa
70
Descirbe the pathway of parathyroid hormone release and its actions
parathyroid hormone release:
1.Low blood calcium concentration will lead to PTH release from parathyroid gland. 2.The release of PTH will then activate Osteoclasts: calcium and phosphorous get related to blood; It will activate VITAMIN D, and will Increase CALCIUM UPTAKE by Intestinal Mucosa. All of these three actions will lead to a rise in blood calcium concentration
71
Describe the various actions of parathyroid hormone
Actions of parathyroid hormone:
- MAJOR REGULATOR of Ca+,. Mg^2+ and Phosphate (HPO4^2-) levels in the blood
1. PTH increases the number and activity of OSTEOCLASTS- elevated bone resorption- Release calcium and HPO4^2- into the blood.
2. Kidneys- SLOWS the rate by which Calcium and Magnesium are lost Into the urine; increases the loss of HPO4^2- into the urine
- hence DECREASES HPO4^2- blood levels; INCREASES Ca^2+ and Mg^2+ blood levels
3. Kidneys- promote the formation of CALCITIROL (active form of Vitamin D)
4. GI Tract- increases the Rate of Absorption of HPO4^2-, Calcium and Magnesium into blood.
72
Describe the process of calcium homeostasis and all of the hormones and organs involved in regulating normal calcium levels
Calcium Homeostasis:
1. Stimulus: FALLING blood Calcium level will cause parathyroid gland to release Parathyroid hormoe (PTH)
- PTH release will then stimulate Calcium release from bones and stimulate Calcium uptake in kidneys
- PTH also leads to activation of Vitamin D and increases Calcium uptake in intestines, causing blood calcium level rises to a set point
2. Stimulus: RISING blood Calcium level causes PARAFOLLICULAR CELLS (C cells) in thyroid gland to release CALCITONIN
- Calcitonin will stimulate calcium deposition in bones and reduce calcium uptake in kidneys, causing blood calcium level declines to a set point.
73
What are the two distinct parts of adrenal glands?
Adrenal glands have two distinct parts: MEDULLA and CORTEX
74
What is the function of medulla and hormones involved?
Medulla; acts to prolong and AUGMENT SYMPATHETIC Effects by Secreting Epinephrine and Norepinephrine
75
What is the function of Adrenal cortex and hormones involved?
Cortex: Secretes Adrenocorticotropic hormones that fit functionally into one of three groups: Mineralcorticoids, Glucocorticoids, and Androgens
76
Differentiate between calcitonin and calcitriol
Calcitonin- helps DECREASES blood calcium levels (help regulate calcium and phosphate levels)
Calcitirol- increases Blood calcium levels
it binds to and activates Vitamin D receptor and increases blood calcium levels (by increasing calcium uptake in intestines)
77
Describe the structure and location of adrenal glands. How many zones does the adrenal cortex have?
Adrenal glands are PAIRED glands which lie superior (on top of) to each kidney
- consists of OUTER ADRENAL Cortex and CENTRAL Adrenal MEDULLA
- Cortex has three zones that secrete hormones.
78
Describe the pathway that leads to adrenal secretions and the hormones involved.
Initially, hypothalamus releases corticotropic releasing hormone (CRH), where it travels to anterior pituitary to stimulate ACTH. ACTH then stimulates the adrenal gland t o secrete different hormones in medulla and cortex portion
Adrenal medulla: will secrete catecholamines: Epinephrine and Norepinephrine
Adrenal cortex: will secrete Mineralcorticoids (Aldosterone, Corticosterone, and deoxycorticosterone), Glucocorticoids (cortisol) and Androgens.
79
What is the role of mineralocorticoids? What hormones makes up majority of mineralcoriticoid and what are its functions?
Mineralocorticoids- regulate the mineral salts SODIUM and POTASSIUM in the extracellular fluid
ALDOSTERONE represents almost 95% of ALL mineralocorticoids produced (majority)
Aldosterone functions:
-Controls total sodium concentration and extracellular fluids
-Stimulates sodium ion reabsorption in the distal tubules of the kidneys
-Helps to stabilize Serum potassium and pH
-Its major effects occur during RECOVERY from physical activity
80
Which zone in the adrenal Cortex secretes mineralocorticoids?
ZONA GLOMERULOSA= secretes mineralocorticoids (aldosterone)- regulates Homeostasis of Na+ and K+, helps adjust blood pressure and blood volume- controlled by Renin-Angiotensin-Aldosterone pathway (RAS)
81
Describe how changes in blood pressure and or blood volume affect different organs in the body. Also discus how stress affects adrenal cortex.
Factor 1: Increase in blood pressure or blood volume stimulates the heart to produce Atrial natriuretic factors that produces INHIBITORY affect on Adrenal cortex (inhibit mineralocorticoid production)
Factor 2: Decrease In blood volume, decrease in Na+ or Increase in K+ in blood stimulates kidney to make RENIN and converts angiotensinogen to And II, which stimulates adrenal cortex
Factor 3: Stress can stimulate hypothalamus to to release CRH which stimulates anterior pituitary to release ACTH and activate adrenal cortex
Factor 4: Decrease in Na+ and increase in K+ in blood stimulate bloodstream (Direct stimulating effect for adrenal cortex)
All of these factors lead to stimulation of adrenal cortex that activates zone glomerulus to increase aldosterone secrete and increase in Na+, H2O absorption; increase in K+ excretion, and cause increase in blood volume and blood pressure.
82
What hormone is the MAJOR glucocorticoids and what are its functions?
CORTISOL is the MAJOR glucocorticoid. IT affects glucose, protein, and free fatty acid metabolism in six ways:
- Cortisol Promotes Breakdown of protein to amino acids
- Supports the action of other hormones
- Serves as INSULIN ANTAGONIST by Inhibiting cellular glucose uptake and oxidation
- Promotes Triacylglycerol breakdown in adipose tissue to glycerol and fatty acids.
- SUPPRESSES immune system function
- Produces Negative Calcium balance
83
Which zone of adrenal cortex are glucocorticoids ? What happens when there are LOW levels of glucocorticoids?
Zona FASICULATA- glucorcorticodis (cortisol, corticosterone, and cortisone)
- contorlled by levels of glucocorticoids and stress
- Low levels of glucorcorticoids induce secretion of Corticotropin-releasing hormone (CRH) from Hypothalamus, then stimulates ACTH form Anterior pituitary and eventually stimulates release of glucocorticoids from adrenal glands (cortex)
84
Describe the factors that stimulate the hypothalamus to relate CRH and the feedback inhibition that occurs with cortisol, ACTH and other hormones involved.
Factors like stress, infection, pain, hypoglycemia, sleep, hemorrhage and trauma stimulate the hypothalamus which releases CRH and stimulates anterior pituitary to release ACTH. The ACTH then causes adrenal cortex to release cortisol and stimulate target tissues
Feedback inhibition: too much cortisol can inhibit the anterior pituitary and reduce the production of ACTH. Too much cortisol can also induce negative feedback and inhibit hypothalamus from release of CRH (which will then lead to lower production of ACTH)
85
List and explain the effects of glucocorticoids
Effects of Glucocorticoids:
1. protein breakdown- liberation of amino acids (primarily skeletal muscle) for New Protein synthesis or ATP production
2. Glucose formation- Liver cells to convert amino acids or lactic acid to glucose for ATP production (gluconeogenesis)
3. Lipolysis- adipose tissue- breakdown of triglycerides and release of fatty acids
4. Resistance to stress- Increased ATP to combat stress from exercise, fasting, fright, temperature extremes, high altitude, bleeding, infection, surgery, trauma and disease.
5. Anti-inflammatory effects- Inhibit WBCs (white blood cells); Inhibit tissue repair
6. Depression of immune responses- high doses inhibit immune response
86
What happens to hormone receptor with too much hormone is produced? exemplify this when too much cortisol is produced. What is the effect of high cortisol levels on target cells?
Down-regulation of receptor occurs when too much hormone is produced (occurs with negative feedback )
High levels of cortisol inhibit CRH production from hypothalamus.
-Too much cortisol will lead to a decrease in glucose uptake in many tissues (eventually lead to decrease in amino acid uptake).
it will also cause increase in adipose tissue synthesis and increase in protein breakdown (decrease protein synthesis). high cortisol levels will also increase gluconeogenesis in the liver.
87
Describe the kind of gonadocorticoids that adrenal cortex produces.
The reproductive organs provide Major source Sex steroids, but the Adrenal cortex produces Gonadocorticoids with similar actions.
Adrenal cortex produces dehydroepiandrosterone (DHEA), which exerts effects similar to Dominant male hormone Testosterone
-Adrenal cortex also produces Small amounts of "Female" hormones Estrogen and progesterone
88
Which zone of adrenal cortex are Androgens (DHEA) in? Also what are effects of androgens in males and females? What stimulates secretion of androgen?
ZONA RETICULARIS -androgens (DHEA)
Males- after puberty, effects of androgen are LOW because most androgens come from testes
Females- androgens promotes libido and converted into estrogens (After menopause, all female estrogens came from the adrenal gland).
The secretion of androgen (DHEA) is Stimulated by ACTH
89
Describe the various roles of the gonadotropic hormones.
Gonadotropic hormones stimulate the male and female sex organs to GROW and SECRETE their hormones at a FASTER rate.
-Follicle stimulating Hormone (FSH)- initiates follicle growth in the ovaries and stimulates these organs to secrete estrogen
-In the male, FSH stimulates germinal epithelium growth in the testes to promote SPERM development
Lutenizing Hormone (LH)- causes estrogen secretion and RUPTURE of follicle, which allows ovum to pass through Fallopian tube for fertilization.
LH also stimulates the testes to secrete testosterone
90
Describe the main function of FSH in males and females and which molecule cause induction and inhibition of the hormone
Follicle stimulating Hormone (FSH):
main function:
Females- Development of several ovarian follicles and Induce follicular cells to Secrete Estrogen
Males- Stimulates Sperm production in testes
Induction: Gonaodtropin-releasing hormone (GnRH) induces release of FSH
Inhibition: Estrogen (females) and testosterone (males) Suppresses GnRH and FSH
-NEGATIVE FEEDBACK
91
Describe the major function of Lutenizing Hormone (LH) in males and females and which molecules is involved in induction and inhibition.
Lutenizing Hormone (LH)-
Function:
females- trigger Ovulation, formation of corpus luteum and induces its release of progesterone; FSH plus LH stimulates secretion of estrogen from ovarian cells (preparation of uterus for implantation of fertilized ovum and mammary glands for secretion)
males- Secretion of TESOSTERONE
-Induction: Gonadotropin releasing hormone (GnRH) induces release of LH
-Inhibition: Estrogen (females) and testosterone (males) suppresses GnRH
-NEGATIVE FEEDBACK.
92
What is main function of prolactin and the molecules that lead to induction or inhibition of the hormone?
Prolactin (PRL)-
Function: initiates and maintains milk secretion by mammary glands (in conjunction with estrogen, progesterone, glucocorticoids, hGH, T4 and Insulin)
Induction: Prolactin releasing hormone (induces Prolactin production)
-inhibition: Prolactin inhibiting hormone (PIH) will inhibit prolactin production
NO NEGATIVE Feedback
93
What makes female and males different? What is the most important androgen that is secreted and its function?
No "male" or "female" hormones exist but rather general DIFFERENCES in Hormone concentrations between the sexes occur
-TESTOSTERONE is the most important androgen secreted
testosterone initiates Sperm production and stimulates the development of male secondary sex characteristics
94
What organ provides the primary source of estrogen? Also describe the functions of estrogen and progesterone
The OVARIES provide the primary source of estrogens
- Estrogens regulates Ovulation, Menstruation, and Physiologic Adjustments during pregnancy.
- Progesterone contributes to Regulatory input to the Female Reproductive cycle, uterine smooth muscle action and Lactation
95
compare the cortisol levels at rest vs after exercise, and benefits of trained individuals
```
At rest (no exercise), Cortisol levels are Low
After exercise (like a swim), Cortisol levels increase due to stress building up, and activating CRH of hypothalamus which induces ACTH release of anterior pituitary, releasing cortisol.
In trained individuals- they have better ability to regulate cortisol levels during exercise due to training adaptations.
```
96
Describe the role of prolactin in the body and what causes prolactin levels to increase and how it may affect females who train intensely.
Prolactin (PRL) initiates an supports milk secretion from the mammary gland
- PRL levels increase at HIGH Exercise intensities and return toward baseline within 45 minutes during recovery
- Repeated exercise-induced PRL release may INHIBIT Ovarian function and contribute to menstrual cycle alterations when females train intensely
97
Describe the adrenal medulla and the cells that it contains. What is the role of chromaffin cells?
Adrenal medulla- modified sympathetic ganglion of the Autonomic Nervous system (ANS)
- Chromaffin cells- hormone producing cells that are Innervated by neurons of the ANS.
- They secrete Epinephrine (Adrenaline) and Neurepinephrine (nonadrenaline)
98
What factors induce hypothalamus to stimulate neurons? What kinds of response does epinephrine and norepinephrine contribute to?
Induced by STRESS and EXERCISE, hypothalamus stimulates sympathetic preganglionic neurons
(causes secretion of chromafin cells, E/NE formation)
-Norepinephrine/Epinephrine Augments the fight or flight response- Increase Heart rate and contractile force- increase blood flow to heart, liver, skeletal muscle and adipose tissue; DILATE airways to lungs (increase O2 consumption); increase blood levels of glucose (for fuel) and fatty acid
99
What type of hormones does adrenal medulla secrete? When will you see a rise in NE/E?
Adrenal medulla secretes CATECHOLAMINES
| During exercise, E/NE increases as exercise intensity reaches more than 50% (Vo2 Max)
100
Differentiate between structures of NE/E. Aldo discuss the target cells that they affect.
NE/ E are similar in structure, except Norepinephrine has methyl group (CH3) and Epinephrine does not.
NE/E stimulate liver (glycogen convert to glucose), Adipose tissue,( TAGs breakdown to FA's and glycerol) and Muscle (blocks glucose entry)
101
What are the major pancreatic hormones ?
Insulin and glucagon
102
What are the major tissues in the pancreas and the hormones that they secrete? What kind of cells do the tissues have?
Two different type so tissues, ACINI and ISLETS of Langerhans compose the pancreas
-The Islets are comprised about 20% Alpha cells that secrete GLUCAGON and 75% Beta cells that secrete INSULIN and a peptide called Amylin
The Acini serve an Exocrine function (ducts) and Secrete Digestive enzymes.
103
Differentiate between the structures of Acini and Pancreatic islets
In the pancreas,
Acini- Clusters or cells that produce digestive enzymes which flow into the Gi tract- exocrine)
Pancreatic islets- (islets of Langerhans)- tiny clusters of Endocrine tissue scattered among the acini.
104
List the 4 types of cells in pancreatic islets and the hormones they secrete?
Pancreatic Islets: 4 types of cells:
* 1. Alpha (a) cells- secrete GLUCAGON
* 2. Beta (B) cells- secrete INSULIN
3. Delta cells- secrete SOMATOSTATIN (growth hormone)
4. F (PP) cells - secrete pancreatic polypeptide
105
Describe the function of glucagon as well as cells in the pancetta that secrete the hormone. Also discuss what controls glucagon output
The Alpha-cells of Islets of Langerhans secrete glucagon (the "insulin antagonist") hormone
-Glucagon primarily stimulates both Glycogenolysis (glycogen breakdown) and Gluconeogenesis by the liver and Increases Lipid Catabolism (breakdown)
PLASMA GLUCOSE Concentration controls GLUCAGON Output by the pancreas
106
Describe the various functions of Insulin. What happens if there is Insufficient insulin?
Insulin regulates glucose entry into all tissues (primary MUSCLE and ADIPOSE) except the brain
-Insulin exerts a HYPOGLYCEMIC effect by Reducing blood glucose concentration
-With insufficient insulin secretion, blood glucose concentration INCREASES, and can ultimately spill in urine.
Insulin's action also triggers INTRACELLULAR enzyme activity that facilities Protein Synthesis.
107
Discuss the primary functions of insulin on target cells like the tissues, adipose, liver and muscle
Effects of Increased Insulin secretion:
-Most tissues: cause INCREASE in glucose uptake (except brain, liver, exercising muscle), increase in Amino acid uptake and Increase in Protein Synthesis; also DECREASES protein breakdown.
-Adipose tissue: Cause INCREASE in Fatty acid and Triacylglycerol synthesis and DECREASES Lipolysis
-Liver and muscle: INCREASE In Glycogen synthesis (store glucose as glycogen), and DECREASE Glycogenolysis
-Liver: INCREASE Fatty acid and Triacylgylcerol synthesis
DECREASE Glycogenolysis.
108
Describe the interaction between glucose and insulin. what happens to insulin when glucose levels change? Also discuss how physical activity affects insulin and glucose levels
Blood glucose levels within the pancreas DIRECTLY Controls Insulin Secretion
- ELEVATED blood glucose levels cause Insulin RELEASE
- A DECREASE in blood glucose concentration Dramatically LOWERS blood insulin levels to provide a Favorable milieu to increase blood glucose
- Physical activity inhibition of insulin output explains why NO excessive insulin release occurs with a concentrated glucose feeding during physical activity.
109
Describe the pathway of insulin in the blood after an increase in blood glucose concentration.
The INCREASE in blood glucose concentration following a meal, induces INSULIN RELEASE from the Beta-cells in the ISLETS of Langerhans
- Insulin then migrates in the blood to target cells throughout the body, where it binds to receptor molecules on cell surface
- Insulin-receptor interaction TRIGGERS a series of events within the cell that enhances glucose uptake and subsequent catabolism or Storage as glycogen or fat.
110
Describe the various secretions and actions of pancreas.
High Blood Sugar: pancreas secretes insulin which will stimulate glycogen formation to lower blood sugar in liver (glucose-> glycogen) and Insulin will stimulate glucose uptake from blood to lower blood sugar.
Low Blood Sugar: pancreas will secrete GLUCAGON which stimulates Glycogen Breakdown (in liver) to raise blood sugar
111
Which cells are part of islet of langherans in pancreas and what hormones do they secrete? What are acini cells ?
Islets of Langerhans (pancreas):
-Alpha cells: secrete glucagon
-Beta cells: secrete Insulin and amylin
Acini cells (secrete DIGESTIVE Enzymes
112
List the steps that occur in the process of HYPOGLYCEMIA
Hypoglycemia
1. LOW blood glucose levels stimulate SECRETION of GLUCAGON (alpha cells)
2. Glucagon accelerates the Conversion of glycogen into glucose and formation of glucose from lactic acid and amino acids in liver cells
3. Hepatocytes (liver cells) Release glucose into blood (causing blood sugar level to rise)
113
List the steps that occur during HYPERGLYCEMIA
Hyperglycemia:
1. HIGH blood glucose levels Inhibits release of Glucagon and STIMULATE Secretion of INSULIN (Beta cells)
2. Insulin acts on many cells in the body to accelerate facilitated diffusion of glucose into glycogen, increase amino acid uptake and protein synthesis and increase synthesis of fatty acids, SLOW conversion of glycogen into glucose, SLOW Formation of glucose from lactic acid and amino acids
3. Blood glucose levels fall
4. LOW glucose levels inhibit the release of insulin
114
Describe the relationship between changes in insulin levels and exercise.
As you exercise, your insulin levels drop as you are burning fuel.
As the intensity of exercise increases (longer the exercise duration), Insulin levels DECREASE, since blood sugar levels are lower and you can become hypoglycemic. This occurs because muscle uptakes glucose to sustain energy for exercising muscles.
115
What signals diabetes? What are the possible causes of diabetes?
A DEFECT anywhere along the pathway for Glucose UPTAKE signals diabetes; possible causes include:
- Destruction of Beta-cells (possibly from pancreatic tumor)
- Abnormal insulin synthesis
- Depressed insulin release (decreased)
- Inactivation of insulin in the blood by blocking agents
- Altered insulin receptors or a DECREASED number of receptors on peripheral cells
- Defective processing of the insulin message within target cells
- Abnormal glucose metabolism
116
Describe the incidence of Type 1 Diabetes and what occurs in the medical condition, How does physical activity affect this condition?
Type 1 Diabetes: (pancreas produces little to no insulin, causing rise in blood sugar)
-Typically occurs in younger individuals and represents between 5 and 10% of all diabetes cases
-Represent an AUTOIMMUNE response, possibly from a single protein that renders the Beta cells Incapable of producing INSULIN and often other pancreatic hormones.
-Type 1 diabetic patients present a more SEVERE abnormality for glucose homeostasis
-Physical activity exerts more- pronounced effects on METABOLIC effect and the management of exercise-related problems
requires greater attention
117
Describe the incidence of Type 2 diabetes and factors that lead to to the condition.
Type 2 Diabetes (MORE Common) :
when there is insulin resistance (body fails to respond normally to insulin)
Tends to occur after age 40, but A sharp increase now occurs in much younger individuals
-Accounts for nearly 95% of ALL diabetes cases in USA.
-Treatment costs exceed $105 billion annually.
-Factors that produce high blood glucose levels in type 2 diabates:
1. Inadequate insulin produced by the pancreas to control blood sugar
2. Decreased insulin effects on peripheral tissue
-Combined effects of BOTH FACTORS (1 and 2)
118
How have obesity rates changed over the years? Which race has highest number of type 2 diabetes cases?
now 15% of children are obese before the age of 20.
| American Indians have highest rate of type 2 diabetes. followed by Asian/Pacific Islander.
119
differentiate between the characteristics of type 1 and type 2 diabetes.
Type 1 diabetes:
Age at onset: usually less than 20 years
Proportion of diabetics: less than 10%
Appearance of symptoms- Acute or subacute
metabolic ketoacidosis - frequent
Obesity at onset- Uncommon
Beta cells- Deceased
Insulin- Decreased
inflammatory cells in islets - present initial
Family history- Uncommon
Type 2 Diabetes: age at onset: Usually greater than 40 (but increasing in children), >90% of all diabetics, Slow appearance of symptoms, rare to have metabolic ketoacidosis, Obesity at onset is COMMON, Variable levels of Beta cells and Insulin; Inflammatory cells in islets- absent ; family history: Uncommon
120
What is metabolic ketoacidosis?
Metabolic Ketoacidosis- life threatening disturbance of metabolism that is seen during diabetes, when high levels ketone bodies (acidic) build up in the body
121
What is Metabolic Syndrome?
| Which organs are affected by untreated metabolic syndrome?
Metabolic Syndrome- a cluster of common conditions (includes Obesity, high blood pressure, high blood glucose, and abnormal cholesterol profile (dyslipidemia) that INCREASES then risk of developing Stroke, Coronary heart disease and Diabetes.
This syndrome affects 25% of adult American
brain, heart and pancreas are affected by untreated metabolic syndrome
-high blood glucose (sugar builds up in bloodstream), high blood pressure (if not treated, causes damage to lining of arteries, fibrous plaque (atherosclerosis)
122
What are the common characteristics o metabolic syndrome? How do you treat metabolic syndrome?
Common characteristics:
-insulin resistance, glucose intolerance, dyslipedemia (high TAG, low HDL, high LDL) , stroke, upper-body obesity, type 2 diabetes, hypertension, coronary artery disease, reduced ability to dissolve blood clots.
-regular monitoring of blood pressure, cholesterol and glucose important for detaching syndrome
Treatment for metabolic syndrome:
1. Weight loss : of up to 5 to 10% body weight improves insulin sensitivity
2. Increased physical activity- reverses insulin resistance, reduces blood pressure, lowers bad cholesterol and reduce overall type 2 diabetes risk
3. Eat a heart healthy diet- reduce saturated fat, cholesterol and salt intake, increase intake of high fiber fruits, veggies an grains
123
Differentiate between normal response to glucose changes, insulin-resistant response, and Type 2 diabetes
Normal response: the rise in blood glucose (after eating) stimulates insulin release from beta cells of pancreas. insulin mediates facilitated diffusion into the cell where glucose combines with a carrier on plasma membrane of muscle
Insulin resistant response- pancreas overproduces insulin (abnormal output) in response to rise in blood glucose as occurs from rapid digestion and absorption of dietary starches and simple sugars Excess insulin production. maintain blood glucose at upper level of normal range. (not type 2 diabetic). But a chronic high insulin output in response to elevations in blood glucose after eating strongly relates to metabolic syndrome .of heart attack, hypertension, obesity, increased risk for stroke
type 2 diabetes- pancreas continues to secrete insulin, however the severity of insulin resistance exceed the pancreas' maximum insulin output to regulate blood glucose within normal range. this result in diagnosis of type 2 diabetes.
124
Describe the effects of increased Glucagon secretion on liver and adipose tissue.
Increase Glucagon secretion:
Liver: Increase glycogenolysis, decease glycogen synthesis, increase gluconeogenesis; increase ketone synthesis, and decrease protein breakdown.
Adipose tissue: Increase lipolysis (breakdown of fats), decrease TAGs synthesis
125
Describe what occurs in conditions of stroke, diabetes, and coronary heart disease.
- Stroke- occurs with sudden death of brain tissue from lack of oxygen. in ischemic stroke, block or reduced blood flow occurs in brain tissues. this blockage may result from atherosclerosis and blood clot formation
- Coronary heart disease- narrowing of coronary arteries can lead to heart attack. Atherosclerosis, (build up plaque in the lining of arteries, causes arterial narrowing) Heart attack causes when blood fails to flow through narrowed coronary vessels which results in ischemic myocardial tissue
- Diabetes- when pancreas produces little or no insulin and body loses ability to respond normally to insulin (insulin resistance). Without insulin, body tissues have less access to essential nutrients for energy and storage.
126
Describe how the different hormones respond to endurance training.
Hormone repose to endurance training:
-Growth Hormone : NO effect on resting values; Less dramatic rise during exercise
-Thyrotropin: No known training effect
-ACTH: Increased exercise values
-Prolactin: some evidence that training LOWERS resting values
FSH, LH, and testosterone: Trained females have DEPRESED (low) values: Reduced testosterone in males (these levels may increase in males with long-term resistance training)
Posterior pituitary hormones: Vasopressin (ADH)- slightly reduced ADH at given workload; Oxytocin- NO research results found
Thyroid hormones (T3, T4): Reduced concentration of total T3 (triiodothyronine) and Increased free thyroxine at rest; increased turnover of T3, and T4 during exercise
Adrenal hormones: Aldosterone: NO training adaptation; cortisol- slight elevation during exercise; Epinephrine/NE: Decreased secretion at rest and at same about exercise intensity after training
Pancreatic hormones: Insulin: Increased sensitivity to insulin; normal decrease in insulin during exercise (greatly reduced wit training) ; Glucagon- smaller increase in glucose levels during exercise at absolute and relative workloads
Renin and angiotensin- NO apparent effect.
127
What other hormones does liver, small intestine and hypothalamus secrete that affect endocrine system?
The LIVER secretes Somatomedins, which affect growth of muscle, cartilage and other tissues
The MUCOSAL Lining of the small intestine secretes Secretin, gastrin, and cholecystokinin to promote and coordinate digestive processes.
The HYPOTHALAMUS Secretes Stimulating or Releasing hormones that activate or release Anterior pituitary hormones .
128
Describe the effects of training on Growth hormone, NE/E, insulin and glucagon
Growth hormone increases with untrained individuals during exercise. compared to trained individuals . This occurs because untrained individuals do not have a lot of GH increase (more steady levels of GH)
-E/NE levels are low at rest and increase after endurance training.
Insulin levels start to decrease during exercise (better able to take up glucose for muscles) . Trained individuals have less insulin secretion during exercise.
Glucagon levels remain STABLE during exercise (little higher in untrained individuals)
129
Further describe the effects of exercise training on skeletal muscle, pancreas and adipose tissue and liver
Exercise training:
- Skeletal muscle increases muscle blood flow, capillary density, muscle glucose delivery and muscle mass, increase glucose storage area all leading to increase in GLUCOSE UPTAKE
-Pancreas: Increases Hyperinsulinemia (Decreased insulin secretion)
Adipose tissue: Decrease abdominal adiposity, decrease TNF-alpha, decrease FFA release (Which decreases gluconeogenesis) , increase insulin receptor density and increase GLUT-4 increase glucose uptake
LIver- Increase insulin sensitivity, and decrease hepatic glucose output.
