-
Name the four mechanisms of intracellular communication?
- 1. Direct - Ions via gap junction
- 2. Paracrine - Paracrine factors via extracellular fluid
- 3. Endocrine - Hormones via blood circulatory system
- 4. Synaptic - Neurotransmitters across neural junctions
-
What is the direct mechanism of intercellular communication?
- By ions via gap junction.
- (sodium, potassium, calcium)
- Cells are touching, gap junction between them
-
What is the Paracrine mechanism of intercellular communication?
- By paracrine factors via the extracellular fluid.
- (chemicals)
- In the same vacinity, gaps between cells, swim back and forth.
-
What is the Endocrine mechanism of intercellular communication?
By hormones via the blood circulatory system.
Travels further communicating with organs across the body
-
What is the Synaptic mechanism of intercellular communication?
- By neurotransmitters across neural junctions
- (nervous system)
- Synaptic cleft
-
What are the six endocrine glands which produce hormones?
- Hypothalamus
- Pituitary Gland
- Thyroid Gland
- Pineal Gland
- Suprarenal Gland
- Parathyroid Gland
- Pancreas
- They are well defined structurally and funtionally
-
What are the endocrine tissues in organs which are capable of producing hormones?
- Kidneys
- Heart
- Intestines
- Thymus
- Gonads
- Adipose Tissue
- Found within organs. Produce hormones to help organ do its job.
-
What are hormones?
Chemical regulators
Secreted into the blood and transported to target cells
Target cells have specific receptors on them
-
What are the five classifications of hormones?
- 1. Steroids
- 2. Monoamines
- 3. Oligopeptides
- 4. Glycoproteins
- 5. Polypeptides
-
What is the chemical structure of steroids?
Lipids (fats) or cholesterol
ex. Vitamin D, sex hormones
-
What is the chemical structure of monoamines?
A single amino acid which is modified or repeated
-
What is the chemical structure or oligopeptides?
3-10 amino acids
ex. Oxytocin in the reporductive system
-
What is the chemical structure of glycoproteins?
Carbohydrate-proteins
ex. luteinizing hormone
-
What is the chemical structure of polypeptides?
Made from 14-199 amino acids
ex. insulin and glucagon
-
What is the cascade of hormone secretion?
- 1. stimulus
- 2. gland (with hormone)
- 3. hormone excretion
- 4. enters the blood stream
- 5. out to receptor of target cell
- 6. action of hormone is manifested
- ex. sugar - - - to - - - - insulin
-
Hormone receptors are protein molecules located on which three parts of the cell?
- 1. Membrane
- 2. Cytoplasm
- 3. Nucleus
-
Where do steroid hormones bind to?
- nuclear receptors
- (nucleus)
- Associated with DNA transcription
-
Where do thyroid hormones bind to?
- Cytoplasmic receptors
- (cytoplasm)
- on mitochondria and ribosomes
-
Where do "all other" hormones bind to?
Cell membrane receptors
They activate a second messenger system (need help getting inside)
-
Are "all other" hormones hydrophobic or hydrophilic?
Hydrophilic
Water soluable not fat soluable.
Attach to receptors in the plamsa membrane. Then the second-messenger activation happens.
-
Are steroid hormones hydrophilic or hydrophobic?
Hydrophobic
Fat soluable only
-
Explain the negative feedback system?
(most common)
endocrine gland hormones reach optium value
inhibits secretion of hypothalamic and anterior pituitary hormones that stimulate the endocrine gland
decreases secretions
-
Describe positive feedback system?
- (rare)
- response to an endocrine gland hormone
hormone reaches optimal level
increases secretions of the hormone that stimulated the response
-
Where is the hypothalamus?
Central area of the basal brain limbic system
-
What does the hypothalamus consist of?
A large number of nuclei that modify and control the body functions via the hypothalamic hormones.
work on the pituitary gland which is the master organ of endocrine system.
-
Name the seven hormones that work on the anterior pituitary gland?
- 1. Growth Hormone Releasing Hormone (GHRH)
- 2. Growth Hormone Inhibiting Hormone (GHIH)
- (Somatostatin)
- 3. Prolactin Releasing Hormone (PRH)
- 4. Prolactin Inhibiting Hormone (PIH) (Dopamine)
- 5. Corticotropin Releasing Hormone (CRH)
- 6. Gonadotropin Releasing Hormone (GnRH)
- 7. Thyrotropin Releasing Hormone (TRH)
-
Name the two Hypothalamic hormones produced by the hypothalamus in posterior pituitary gland?
- 1. Antidiuretic Hormone (ADH)
- 2. Oxytocin (OT)
-
What is the pituitary gland?
- A small gland that is connected to the hypothalamus by the infundibulum.
- It had two parts
- Anterior pituitary gland (Adenohypophysis)
- Posterior pituitary gland (Neurohypophysis)
-
What is the Posterior Pituitary Gland called?
Neurohypophysis
-
What is the Anterior Pituitary Gland called?
Adenohypophysis
-
What is the posterior pituitary gland derived from and what does it connect and how?
- Derived from the neural brain tissue
- Connects the hypothalamus to the posterior pituitary gland by the Hypothalamic Hypophuseal Tract axons
-
What is the anterior pituitary gland derived from and what does it connect and how?
- Derived from ectodermal tissue in the roof of the embryonic mouth
- Connects the hypothalamus to the anterior pituitary gland by the Hypothalamic Hypophyseal Portal System.
- Seperior hypophyseal artery brings blood into the capillary beds of the Adenohypophysis of Pituitary gland. Hypophyseal veins carry blood away.
-
Where is Oxytocin (OT) made, stored and secreted from?
- Oxytocin is made in the Hypothalamus
- Ocytocin is stored in the Posterior Pituitary Gland
- Oxytocin is secreted from the Posterior Pituitary Gland
-
What is the target tissue of Oxytocin (OT)?
Smooth muscle of the reproductive system in both males and females.
-
What does Oxytocin (OT) stimulate?
- Stimulates semen propelling during ejaculation
- Stimulates uterine contractions during labor
- Stimulates milk ejection during suckling
-
What is the abbreviation of Oxytocin?
OT
-
What is the abbreviation of Antidiuretic Hormone?
ADH
-
What is the second name for Antidiuretic Hormone (ADH)?
Vasopressin
-
Where is Antidiuretic Hormone (ADH) (Vasopressin) made, stored, and secreted?
- Made in the hypothalamus
- Stored in the Posterior Pituitary Gland
- Secreted from the Posterior Pituitary Gland
-
What are the targetr tissues for Antidiuretic Hormone (ADH) (Vasopressin)?
Target tissues are kidneys and blood vessels
-
What does Antidiuretic Hormone (ADH) (Vasopressin) do?
- Increases waterreabsorption in the kidneys to increase blood volume
- Causes vadoconstriction of blood vessels to increase blood pressure
-
What is the abbreviation of Human Growth Hormone?
- hGH
- 190 Amino acids in humans
-
What controls the secretion of hGH?
Secretions are controlled by hypothalamic GHRH (Growth Hormone Releasing Hormone) and GHIH (Growth Hormone Inhibiting Hormone)
-
What are the target cells for hGH?
All cells especially skeletal and muscle tissue
-
What is stimulated by the hGH?
- Directly stimulates stem cell growth and differentiation
- Stimulates liver systhesis and release of somatomedins
- Somatomedins mediates growth hormone functions by stimulating stem cell growth and differentiation.
- Results in growth to adulthood and maintenance of skeleton and muscles in adulthood
-
What do somatomedins do?
Somatomedins mediates growth hormone functions by stem cell growth and differentiation
-
What are the three Human Growth Hormone (hGH) Imbalances?
- Pituitary Dwarfism
- Gigantism
- Acromegaly
-
What is pituitary dwarfism is caused by?
hyposecretion (decreased secretion hGH) in children and adolescents
-
What is gigantism caused by?
hypersecretion (increased secretion of hGH) in infants and children
-
What is Acromegaly caused by?
- hypersecretion (increased secretion of hGH) in adults resulting in distorted facial bones and features.
- (flat bones and soft bones will continue to grow)
-
What is Thyroid Stimulating Hormones abbreviation?
TSH
-
What controlls the secretion of Thyroid Stimulating Hormone (TSH)?
Secretions controlled by hypothalamic TRH (thyroid releasing hormone)
-
-
What is the target tissue for TSH?
Targets the thyroid gland
-
What does TSH stimulate?
Secretions of the thyroid hormones
-
What are the abbreviation for Adrenocorticotropic Hormone?
ACTH
-
What controlls the ACTH?
Secretions controlled by hypothalamic CRH (cortiotropic releasing hormone)
-
What is the target tissue of the ACTH?
Targets the Adrenal gland cortex
-
What does ACTH stimulate?
Stimulates secretions of the adrenal gland cortex hormones.
-
What is the abbreviation for Prolactin?
PRL
-
What controls the secretion of PRL?
Secretions controlled by hypothalamic PRH (Prolactin Releasing Hormone) and PIH (Prolactin Inhibiting Hormone)
-
What is the target tissue of PRL?
Targets mammary glands
-
What does PRL stimulate?
Stimulates milk systhesis in the mammary glands
-
What controls the secretion of gonadotropoins?
Secretions controlled by hypothalamic GnRH
-
What is the abbreviation for Follicle Stimulating Hormone?
FSH
-
What is the abbreviation for Luteinizing Hormone?
LH
-
The Anterior Pituitary hormone secretion is stimulated by releasing hormones (RH's) from the hypothalamus through what?
Hypophyseal Portal System
-
The Anterior Pituitary hormone secretion is inhibited by releasing ihibiting hormones (IH's) from the hypothalamus through what?
Hypophyseal Portal System
-
Control of Anteroir Pituitary gland hormone secretion is controlled by which feedback system?
All controlled by negative and positive feedback systems
-
Where is the pineal gland located?
In the roof of the third ventricle of the brain.
-
What does the pineal gland contain?
- Neurons
- Neuroglia
- Pinealocytes that secrete melatonin
-
When in melatonin secretion the highest?
At night
-
When in melatonin secretions the lowest?
During the day
-
What are the three functions of Melatonin?
- Timing of sexual maturity
- Protection
- Circadian rhythm setting
-
What does melatinon deficiency due to children?
- Causes premature puberty in children
- (ages 4-5)
-
What does Melatonin protect against?
Protection in the CNS against damage by free radicals
-
What does melatonin do for the Circadian Rhythm Cycle?
- Increasaed melatonin secretion may cause Seasonal Affective Disorder (SAD) during winter.
- AKA Winter Depression
-
Where is the thryoid gland look like and located?
- Large butterfly-shaped gland in the neck below the voice box (larynx)
- It had two lobes connected by an isthmus
- made of follicles filled with a colloid (gel-like material)
-
What is the bridge connecting the two lobes of the thyroid?
Isthmus
-
What are the follicles of the thyroid filled with?
Colloid (gel-like material)
-
What protein is stored in the colloid of follicle?
Thyroglobulin
-
Thyroid hormone systhesis is stimulated by what?
Hypothalamus secretes TRH to the Anterior Pituitary which secretes TSH to the Thyroid gland.
-
What are the 8 steps in Thyroid Hormone Synthesis?
- 1. Iodide trapping by folicular cells (from blood) and transported into follicular lumen.
- 2. Synthesis of thyroglobulin by follicular cells and transported into follicular lumen.
- 3. Oxidation of iodide to iodine in lumen by thyroid peroxidase enzyme
- 4. Iodination of tyrosine molecules in the thyroglobulin chain to form T1 and T2.
- 5. Coupling of T1 and T2 to make T3 or T4.
- 6. Pinocytotsis of thyroglobulin chain by the follicular cells and digestion by lysosomal enzymes to produce free T3 and T4.
- 7. Secretions of T3 (Triiodothyroanine) and T4 (Tetraiodothyronine/Thyroxine) into the blood.
- 8. Transport of T3 and T4 in blood in the free form or bound to thyroid-binding-globulin (TBG)
-
What do Parafollicular C cells produce?
Calcitonin
-
What are the Thyroid Hormone function of T3 and T4?
- 1. Increase the Basal Metabolic Rate (BMR) of all cells
- 2. Increase ATP production in mitrochondria of all cells by areobic cell respiration.
- 3. Promote normal growth synergistically (in collaberation with) with growth hormone
-
What does Calcitonin do?
- Decreases blood calcium levels
- (produced by C-cells)
- (works with parathyroid hormone)
-
Name the 4 thyroid gland disorders?
- 1. Cretinism (thyroid dwarfism)
- 2. Endemic goiter
- 3. Hypothyroidism (in adults)
- 4. Hyperthyroidism (in adults)
-
What is Cretinism (thyroid dwarfism) and what does it cause?
- Hypothyroidism during fetal development or during early infancy.
- Causes sever forms of mental and physical retardation in the newborn child. (if left untreated life span of 2 years, if treated with in 4 months it is reversable)
- Retardation is reversable only if horminal replacement therapy is started during the first 4 months of the newborns life.
-
What is Endemic goiter and when does it occur?
- Hypothyroidism caused by iodine deficiency
- Insufficient dietary iodine to make T3 and T4
- Occurs mostly in arid, dry, desert inland regions
- Lack of negative feedback from T3 and T4 causes over stimulation and overgrowth of the thryoid gland by TRH and TSH
- goiter results (enlarged throid gland)
-
What is Hypothyroidism (in adults) and what are the symptoms?
- Caused by too little T3 and T4
- Symptoms are:
- Decreased Basal Metabolic Rate (cell energy)
- Decreased Body Temp
- Cold intolerance
- Bradycardia
- Lethargy
- Weight gain
- Goiter
- Myxederma (fish skin, dry, scaley)
-
What is Hyperthyroidism (in adults) and what are the symptoms?
- Too much T3 and T4
- Grave's disease is the most common cause (autoimmune disorder)
- Symptoms:
- Increased Basal Metabolic Rate
- Increased Body Temp
- Heat intolerance (miserable in hot areas)
- Tachycardia
- Anxiety & irritability
- Weight loss
- Goiter
- Exophthalmia (exophthalmos) bulging eyeballs
-
What are the parathyroid glands?
Four small glands on the posterior surface of the thyroid gland
-
What cells do the parathyroid gland contain and what does that cell secrete?
Contains Principal cells that secrete Parathyroid Hormone
-
What does Parathyroid Hormone regulate?
Along with Calcitonin they regulate blood calcium levels
-
What does Calcitonin do?
- Decreases blood calcium by:
- Increasing calcium excretion by the kidneys (out of blood and into urine by kidneys)
- Increasing calcium deposition in the bones
-
What does the Parathyroid Hormone do?
- Increases blood calcium by:
- Increasing calcuim reabsorption by kidneys (from urine back into the blood)
- Releasing calcium from bones into blood
- Activating Vitamin D which increases calcium absorption from intestines into the blood
-
What is another name for the suprarenal glands?
- Adrenal Glands
- (located ontop of the kidneys)
- They have 3 zones
- Capsule, Cortex and Medulla
- Medulla is a gland all on its own producing different hormones.
-
Suprarenal Cortex Zona Glomerulosa, or the outer and 1st zone secretes what?
- Outer zone secreting mineralocorticoids.
- (Minerals - Sodium and Potassium)
-
What is the major Mineralocortocoid in the Zona Glomerulosa or 1st zone of the suprarenal cortex and what does it do?
- Aldosterone is the major mineralocorticoid
- Increases retention of sodium by kidneys (takes back from urine into blood)
- Increases excretion of potassium by kindeys (potassium from blood into urine)
- Increases water retention and blood volume (increased blood volume = increased blood pressure)
-
What regulates Aldosterone in the Zona Glomerulosa or 1st zone of the suprarenal cortex?
Aldosterone secretion is regulated b sodium and potassium levels in the blood
-
Suprarenal Cortex Zona Fasciculata or the middle zone and 2nd zone secretes what?
Middle zone secreting glucocorticoids
-
What is the major Glucocortiocoid in the Zona Faciculata or the 2nd zone of the suprarenal cortex and what does it do?
- Cortisol is the major glucocortiocoid
- Increases glucose and glycogen systhesis (cells make more glycogen/glucose)
- Incease fatty acids (glucose) & protein (glycogen) breaking
- Reduces inflammation and allergic rashes
-
What glands regulates the secretion Cortisol?
Hypothalmic CRH (cortiotropic releasing hormone) and Anterior Pituitary ACTH (adrenal corticotropic hormone)
-
Suprarenal Cortex Zona Reticularis or the inner zone or 3rd zone secretes what?
- Inner zone secreting androgens (male sex hormone)
- (5% of male hormones come from Zona Reticularis and 98% from testes)
-
What does the secretions of androgen do for the female body in the Zona Reticularis?
- Stimulates pubic hair growth in puberty
- promote muscle mass, formation of the blood cells and libido in females
-
What regulates androgen?
Hypothalamic CRH (cortiotropic releasing hormone) and anterior pituitary ACTH (adrenal cortioctropic hormone)
-
The two Suprarenal gland disorders are?
- Addison's desease
- Cushings disease
-
What is Addison's Disease?
- Suprarenal gland disorder
- Insufficient suprarenal cortex secretions
- Lack of energy
- weight loss
- inability to resist stress
- loss of sodium and water in urine
- John F. Kennedy had this disease
-
What is Cushing's Disease?
- Suprarenal gland disorder
- Excessive suprarenal cortex secretions
- muscle wasting due to breakdown of proteins
- spindly thin arms and legs
- body fat redistribution
- rounded face (moon face)
- Fatty hump between shoulders (buffalo hump)
- Large abdomen with hanging-down fat
- Virilization (facial hair) and musculinization (muscles) in females
-
What kind of tissue is the Suprarenal Medulla made of?
Develops from the same nervous tissue as the sympathetic nervous system
-
Where are the Chromaffin cells located?
- Suprarenal Medulla
- Chromaffin cells receive direct innervation from the sympathetic nervous system
-
What increases hormone secretion by the adrenal medulla?
sympathetic stimulation
-
The adrenal medulla hormones are exactly the same in structure and function as what?
- sympathetic nervous system neurotransmitters
- - their effects mimic those of the SNS
- - they cause fight or flight behavior
-
Catecholamines are the collective name for what?
Epinephrine and norepinephrine
-
Suprarenal hormones are a back-up system for what?
sympathetic nervous system
-
What do catecholamines target?
targets all body cells
-
Catecholamines fight or flight reactions are what?
- increased heart rate and strength
- increased blood flow to skeletal muscles, heart and brain
- increased dilation of airways
- increased fuel for energy
- increased blood pressure
-
Describe the pancreas.
- 5 inches long with a head, neck, body and tail
- most are exocrime cells producing digestive enzymes
- endocrine cells in pancreatic islets produce hormones
-
What is the other name for the pancreatic islets?
Islets of Langerhan
-
Name the 4 pancreatic islet hormones, their % and what they produce.
- alpha cells (20%) glucagon
- beta cells (70%) insulin
- delta cells (5%) somatostatin (brake controller for glucagon and insulin)
- F-cells (5%) pancreatic polypeptide (PP-cells)
-
What does insulin do?
- Insulin decreases blood glucose by:
- 1. Increasing uptake of glucose into cells (cells take glucose from blood)
- 2. Increasing synthesis of glycogen (storage form of glucose) in the liver for storage
- Insulin increases protein synthesis in cells
- Insulin increases fat synthesis in cells
-
What does glucagon do?
- Glucagon increases blood glucose by:
- 1. Increasing synthesis od glucose from amino acids in the liver (making new)
- 2. Increasing breakdown of liver glycogen into glucose (already stored)
- 3. Increasing the release of glucose from liver into blood
- Glucagon increases fat breakdown in adipose tissue to free fatty acids (Lypolysis)
-
What is high blood glucose after a meal called and what does it stimulate and inhibit?
- Fed State
- stimulates the secretion of insulin and inhibits the secretion of glucagon
-
What is low blood glucose between meals called and what does it secrete and inhibit?
- Fasting State
- stimulates the secretion of glucagon and inhibits the secretion of insulin.
-
What is Deabetes Mellitus?
A metabolic disorder that produce high glucose levels in the blood. (Hyperglycemia)
-
What causes Diabetes Mellitus?
- caused by genetic defects that
- 1. decrease insulin secretions
- 2. produce defective insulin
- 3. defective insulin receptors
-
What is the other names for Type 1 Diabetes Mellitus?
- Juvenile Diabetes
- Insulin-Dependent-Diabetes-Mellitus (IDDM)
-
What are the characteristics of Type 1 Diabetes Mellitus?
- Usually develop in people younger than 7 years of age
- Beta cells are destroyed by own immune system
- Insulin levels are low or absent
- Insulin injections are required for life
-
What are the other names for Type 2 Diabetes Mellitus?
- Adult Diabetes
- Non-Insulin-Dependent-Diabetes-Mellitus (NIDDM)
-
What are the characteristics of Type 2 Diabetes Mellitus?
- Most common type of Diabetes (90%)
- Mostly in people over 35 who are obese
- Insulin may still be secreted but the body cells are less sensitive to insulin actions due to blocking of the insulin receptors
- may be controlled by diet
- insulin injections may not be required (as long as beta cells are still alive)
-
What are the 3 signs of Diabetes Mellitus?
- the 3 P's
- Polyuria - excessove urination
- Polydypsia - excessive water drinking
- Polypahgia - excessive eating
-
What is the job of the intestinal endocrine tissue and what are the important hormones?
- Intestinal hormones coordinate activities of the digestive system
- Most important ones are Cholecystokinin (CCK), Gastrin and Secretin
-
What are the hormones of the Kidney's endocrine tissue and what do they do?
- Calcitriol - is the active form of vitamin D that increases calcium absorption from the intestine.
- Erythropoietin - stimulates RBC production
- Renin(enzyme)-Angiotensin-Aldosterone - system affect blood volume and blood pressure
-
What is the hormone that the heart endocrine tissue has and what does it do?
Natriuretic Peptide - increases sodium and water excretion by the kidneys to decrease the blood volume if the heart is struggling with too much blood
-
What is the hormone that the Thymus endocrine tissue secretes and what does it do?
Thymosins - promote development and maturation of the T-Lymphocytes
-
What does the hormone of the Gonad endocrine tissue secrete?
- Testosterone and Inhibin in testes
- Estrogen and Progesterone in ovaries
-
What is the hormone secreted by the adipose tissue and what does it do?
Leptin - suppress appetite
-
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