Term
| Simply put, growth is defined as a complicated series of events that increases both ____________ and ___________. |
|
Definition
Cell Size (hypertrophy)
and
Cell numbers (Hyperplasia) |
|
|
Term
| What 3 things modulate growth? |
|
Definition
1. Genetics
2. Diet
3. Hormone balance |
|
|
Term
| Which hormones increase growth? |
|
Definition
1. GH
2. T4 and T3
3. Insulin
4. andorgens (male sex steroids - like testosterone in males)
|
|
|
Term
| Which hormones decreases growth? |
|
Definition
1. Adrenal steroids (cortisol)
2. Female sex steroids (estrogens) |
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|
Term
| Growth Curve is split up into 3 stages. What are they? |
|
Definition
Stage 1 = Prepurbertal growth
Stage 2 = Pubertal growth
Stage 3 = Adult growth |
|
|
Term
| In prepubertal growth there is a greater growth rate in the ________ than the ___________. |
|
Definition
|
|
Term
| Pubertal Growth is characterized by ______________ and lasts for 2-3 yrs. This leads to an increase in both extremity and trunk growth. |
|
Definition
|
|
Term
| T/F: Females mature faster than boys because puberty is delayed in males by about 2 yrs. |
|
Definition
|
|
Term
| In Adult growth is there is only _________ growth and in fact can even start to shrink in the 6-7th decade of life. |
|
Definition
| trunk (lateral- get wider) |
|
|
Term
| Which 2 hormones are very similar in structure and have the same MW? |
|
Definition
Growth Hormone (191 A.A.) and Prolactin (198 A.A.)
|
|
|
Term
| Where is GH released from? |
|
Definition
| Somatotropes that are GH producing cells in the Anterior Pituitary (AP) |
|
|
Term
| Somatotropes make up how much of the AP cell population? |
|
Definition
|
|
Term
|
Definition
| Secreted directly into the blood and is bound to plasma by GH Binding Proteins |
|
|
Term
| Why is the binding of GH to binding proteins on the plasma important? |
|
Definition
| Because it increases the half life to about 20-30 mins. If not bound then would degrade in 2 mins. |
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|
Term
| GH is released in ____________ pulses throughout the day and is higher in _________________. |
|
Definition
|
|
Term
| T/F: There is an increase in GH when you go to sleep. But it must not be interupted. |
|
Definition
True
About 70% of GH is released when asleep. Helps you to grow in height! |
|
|
Term
| During stress and exercise, GH levels ___________. |
|
Definition
|
|
Term
| Which A.A. stimulate GH and which Vitamins/co-factors? |
|
Definition
A.A. = Arginine, ornithine, lysine, proline, glycine and glutamine
Vit B3
Niacin |
|
|
Term
| When does GH secretion decrease? |
|
Definition
| With age and with obesity |
|
|
Term
| GH secretion rises to peak levels during _______________ and ________________ |
|
Definition
| puberty and early stages of adult life |
|
|
Term
| How many forms of GH releasing hormone (GHRH) are there? |
|
Definition
2 forms
40 A.A. and 44 A.A |
|
|
Term
| Where is the cell body of the GHRH located? |
|
Definition
| In the arcuate region of the hypothalamus |
|
|
Term
| Which 28 A.A. peptide from the stomach has show to be a potent stimulator of GH secretion? |
|
Definition
|
|
Term
| T/F: Ghrelin acts on the same receptor as GHRH. |
|
Definition
| False; it acts on a different receptor than the GHRH on the somatotrope. It acts on the GH Secretagogue receptor |
|
|
Term
| How many forms of somatostatin (SRIF) are there? And which is more potent? |
|
Definition
2 forms
14 A.A. and 28 A.A. (more potent) |
|
|
Term
| Where are the cell bodies located for SRIF? |
|
Definition
| In the perventricular area of the hypothalamus |
|
|
Term
| With SRIF there is said to be prolonged periods of ____________ GH secretion. |
|
Definition
|
|
Term
| Which NTs seem to regulate the release of both GHRH and SRIF? |
|
Definition
|
|
Term
| What does IGF - 1 do in the brain in reference to GHRH release? |
|
Definition
| Decreases GHRH rlease and increases the SRIF release leading to a decrease in GH. |
|
|
Term
| How does IGF-1 affect the AP? |
|
Definition
| It interferes with GHRH binding thus decreases GH. |
|
|
Term
| In the short loop feedback, GH __________ the GHRH release and ______________ the SRIF release in the brain. |
|
Definition
|
|
Term
| What mediates the action of GH? |
|
Definition
| IGF or Insulin like growth factors |
|
|
Term
| What are the 2 forms of IGFs? |
|
Definition
1. IGF-1 = GH dependent
2. IGF-2 = not GH dependent |
|
|
Term
| ______ induces synthesis and release of IGF-1 |
|
Definition
|
|
Term
| T/F: Since IGF-2 is not GH dependent it has most of the insulin like activity. |
|
Definition
|
|
Term
| What is an endocrine function of IGF-1? |
|
Definition
Released from liver into blood where it circulates in plasma bound to binding proteins which protect the peptides from proteolysis.
(increases its half life) |
|
|
Term
| Target organ of GH is ___________ where it has effects on _______ within the body and modulates the _____________. |
|
Definition
whole body
metabolism
formation of bone |
|
|
Term
| What are some metabolic effects of GH in proteins? |
|
Definition
1. increases protein synthesis
2. Increase intracellular mRNA levels
3. decreases catabolism of proteins
4. mobilizes A.A. into cells
(ANABOLIC ACTIONS) |
|
|
Term
| What is the metabolic effect of GH in lipids? |
|
Definition
| Mobilizes free fatty acids from lipids. |
|
|
Term
| What are the 2 phases metabolic effects of GH in Carbohydrates? |
|
Definition
1. Initial action is to increase Gluc uptake into cells therefore decrease the blood Gluc levels (Insulin like action)
2. Thru time the blood Gluc levels are increased by GH because GH decreases the cellular Gluc utilization (Anti-Insulin like action) |
|
|
Term
| How does GH promote bone remodeling via endocrine actions? |
|
Definition
| GH increases the formation of osteoblasts and osteoprogenitor cells (bone precursor cells) |
|
|
Term
| How does GH promote bone remodeling via paracrine/autocrine IGF-1 actions? |
|
Definition
| It increases the activity of osteoblasts and osteocytes to make organic matrix. This increases the synthesis of both collagen and ground substance. |
|
|
Term
| What are the types of bones? And what % do they make up? |
|
Definition
1. Cortical (compact) = 80%
2. Trabecular (cancellous/spongy) = 20% |
|
|
Term
| Cortical bone is mainly in _______________ whereas trabecular is found in ____________________. |
|
Definition
1. Appendicular skeleton
2. Skull and center of vertebrae, ends of long bones - epiphyses |
|
|
Term
| What is the bone composition? |
|
Definition
1. Organic matrix = 30-40%
2. Bone salts = 60-70% |
|
|
Term
| The organic matrix is mainly __________, and ground substance. |
|
Definition
collagen (90%)
ground substance (10%) |
|
|
Term
| What is in the ground substance? |
|
Definition
Proteoglycans
chondrotin sulfate and hyaluronic acid
glycoproteins
lipids. |
|
|
Term
| The organic matrix is said to give bone there _____________. |
|
Definition
|
|
Term
| Bone salts are said to give bone there _______________. |
|
Definition
|
|
Term
| What makes up the bone salts? |
|
Definition
Hydroxyapatite
Ca10(PO4)6OH2 |
|
|
Term
| What are some clinical features of pituitary dwarfism? |
|
Definition
1. proportional short stature
2. "doll face" - small chin, stumpy nose, thin lips
3. Normal IQ
4. Soft, pliable skin (no wrinkles early age, then premature wrinkling as ages)
5. Soft hair, very thin and lack of facial hair
6. Delayed puberty and secondary sexual characteristics = small genitalia
7. high pitched voice
8. truncal obesity |
|
|
Term
| Pituitary Dwarfism results from a ___________ in GH. |
|
Definition
|
|
Term
| What are 3 causes of Pituitary Dwarfism? |
|
Definition
1. Genetics = 10%
2. Tumors/Apoplexy = 60%
3. GH receptor defect = 30% |
|
|
Term
| With genetic Pit. Dwarfism there is reduced ____________ release from the hypothalamus thus altered or no GH release from the pituitary. |
|
Definition
|
|
Term
| T/F: Tumors in the hypothalamus that compress GHRH containing tissues and infarct/necrosis of pituitary can lead to Pit. Dwarfism. |
|
Definition
|
|
Term
| What is so special about a Laron dwarf? |
|
Definition
They have an increase in GH levels in the blood but a decreased GH binding protein in the serum.
They have a defect in the GH receptor.
(High GH but no growth) |
|
|
Term
| With excess GH there is accelerated growth. What are the 2 forms? |
|
Definition
1. Pituitary Giantism
2. Acromegaly |
|
|
Term
| Who is the tallest guy? and how did he die? |
|
Definition
Robert Wadlow
8"11 and 475 lbs
Died of cellulitis of the feet at the age of 22 |
|
|
Term
| With Pituitary Giantism there is accerelated growth during ____________ as a result of increase GH secretion from the pituitary. |
|
Definition
|
|
Term
| What is the main cause of Pit. Giantism? |
|
Definition
| Usually a GH secreting tumor |
|
|
Term
| T/F: Pit. Giantism peeps have unproportional growth. |
|
Definition
| False; they have proportional growth |
|
|
Term
| What are some characteristics of peeps with Pit. Giantism? |
|
Definition
Thick skin with decreased subcutaneous fat
Delayed puberty = "eunichoid" appearance |
|
|
Term
| Pit. Giantism is associated with growth prior to ____________________. |
|
Definition
| Closure of the epiphyseal plates |
|
|
Term
| Acromegaly is GH excess after ________________ so it is adult associated. |
|
Definition
|
|
Term
| Peeps with Acromegaly have an higher plasma concentration of both ____________ and ___________. |
|
Definition
|
|
Term
| What are some clinical features of peeps with Acromegaly? |
|
Definition
1. facial disfiguring = Frankensteinian look
2. Profuse sweating
3. Barrel chest
4. deep voice
5. Enlarged organs
6. Sexual dysfunction
7. Impaired Gluc tolerance |
|
|
Term
| What are some causes of Acromegaly? |
|
Definition
1. Pituitary adenoma
2. Tumors in the hypothalamus, pancreas and lung - which all secrete large amounts of GHRH which results in hyperplasia of pituitary and increase GH. |
|
|
Term
| What are the 3 possible treatments for Acromegaly? |
|
Definition
1. Surgery to remove tumor
2. Radiation
3. Medical Theraphy |
|
|
Term
| What is significant in the use of DA to treat Acromegaly? |
|
Definition
| Usually, DA stimulates GH but with people with Acromegaly it inhibts GH thus shrinks the size of the tumor. |
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