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Physiology
Exam 6
238
Physiology
Professional
12/04/2012

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Term
True or False:

Paracrine hormones are locally acting.
Definition
True
Term
What brings about the desired result in a chemically gated receptor channel
Definition
Ion entry
Term
Describe how a receptor enzyme works.
Definition
Extracellular messenger binds which activates protein kinase and protein kinase activates designated protein bringing about the desired response.
Term
G-proteins activate ___________
Definition
effector proteins
Term
Effector proteins produce _____
Definition
Second messengers
Term
What is the role of second messengers in g-protein coupled receptors?
Definition
To activate protein kinase
Term
What are the two types of lipophilic (fat soluble) hormones?
Definition
Thyroid and Steroid hormones
Term
True or False:

Thyroid hormone is hydrophilic
Definition
False

Hydrophobic
Term
What category of hormones does FSH and LH fall under?
Definition
Glycoproteins
Term
True or False:

Oxytocin and Growth hormone both are peptides and hydrophilic
Definition
True
Term
Where is tyrosine secreted from? Tryptophan?
Definition
Tyrosine - adrenal medulla

Tryptophan - Pineal gland
Term
True or False:

Tryptophan is a catecholamine
Definition
False

Indolamine
Term
True or False:

Tyrosine is a catecholamine
Definition
True
Term
Describe the synthesis of hydrophilic peptide hormones (3 basic steps).
Definition
1) DNA is transcribe to RNA
2) RNA is translated to protein
3) Protein is stored or released
Term
Where does RNA translation occur during hormonal synthesis?
Definition
Rough ER
Term
During hormonal synthesis, where are proteins stored until they are released? What is the process called which releases these proteins?
Definition
Stored in secretory vesicles until released by exocytosis
Term
Describe the synthesis of lipophilic steroid hormones.
Definition
A common precursor is used followed by a series of enzymatic steps
Term
Where are lipophilic hormones stored?
Definition
Trick question, they are NOT
Term
True or False:

Steroid hormone secretion depends upon the rate of synthesis.
Definition
True
Term
True of False:

All hydrophilic hormones are dissolved in the blood
Definition
False

All except for catecholamines which 50% are bound to albumin
Term
True or False:

Lipophilic hormones are reversibly bound to plasma proteins
Definition
True
Term
How is it possible for fat soluble hormones to evoke non-gene-activating activities?
Definition
By binding to membrane-bound receptors.

This is only possible with some sex steroids
Term
How do the majority of fat soluble hormones act?
Definition
Through gene activation
Term
Once a lipophilic hormone diffuses through the plasma membrane and binds with its receptor, what occurs?
Definition
The hormone-receptor complex will bind with DNA's hormone response element.
Term
Once the hormone-receptor complex binds at its respective location, describe the steps leading up to the desired response.
Definition
1) Binding activates gene
2) Activated gene transcribes mRNA
3) mRNA leaves nucleus
4) Ribosomes read mRNA to synthesize new proteins
5) New protein is released from ribosome and processed into final folded form
6) New protein brings about desired response
Term
True or False:

Endocrine glands are those which contain ducts.
Definition
False

Ductless glands
Term
What is a hormonal stimulation?
Definition
A hormone stimulates release of another hormone
Term
What is a humoral stimulation?
Definition
A substance in body fluid stimulates release of hormone
Term
True or False:

The pituitary constantly secretes hormones
Definition
False

Secretion rates vary
Term
What type of control system regulates blood glucose?
Definition
Negative-feedback control
Term
The hypothalamic-anterior pituitary-gonadal axis is regulated by what control system
Definition
Negative-feedback control
Term
Increasing oxytocin will have what effect on prostglandin?
Definition
It will increase prostaglandin production
Term
What effect will increasing oxytocin and prostaglandin have in regards to child birth?
Definition
It will increase uterine contractions
Term
What effect will increasing uterine contractions have in regards to child birth?
Definition
It will increase oxytocin secretion
Term
What type of reflex is an adrenaline rush?
Definition
Neuroendocrine reflex
Term
What is another name for circadian rhythms?
Definition
Diurnal rhythms
Term
Over a 24 hour span, when is a hormonal response at its highest peak?
Definition
During the first few hours
Term
Why does a primary hyposecretion occur?
Definition
Glandular abnormality
Term
Why does a secondary hyposecretion occur?
Definition
Lack of stimulus by tropic hormone
Term
What are the two functions of tropic hormones?
Definition
Stimulate an endocrine organ to grow and secrete its hormone
Term
What are the two main reasons for an abnormal target-cell response?
Definition
1) Lack of receptors
2) Lack of cellular component in the response pathway
Term
Why does a chronic increase in insulin lead to a lower number of receptors and thus increased blood glucose?
Definition
Because insulin will bind to an insulin receptor which is then internalized within a cell. This process occurs much quicker than an empty receptor can be replaced.
Term
What is permissiveness?
Definition
One hormone must be present for the full effect of another hormone
Term
What effect will epinepherine have by itself compared to epinepherine and thyroid hormone together?
Definition
Epinephrine alone will have a small increase in glucose and fatty acids within the blood where as epinephrine and thyroid hormone together will show a large increase in glucose and fatty acids in the blood.

This is a prime example of permissiveness
Term
What is synergism?
Definition
Several hormones combine to produce a greater effect than one alone.
Term
What part of the brain is known as the integration center?
Definition
Hypothalamus
Term
What are the potential effects of the hypothalamus on the anterior pituitary?
Definition
The hypothalamus can stimulate or inhibit the anterior pituitary hormone secretion via releasing and inhibiting hormones.
Term
True or False:

The posterior pituitary synthesizes its own hormones.
Definition
False

The hypothalamus does
Term
What is the suprachiasmatic nucleus? What is its function?
Definition
Cluster of neuron cell bodies above optic chiasm

Functions to establish inherent daily rhythms
Term
Where does the suprachiasmatic nucleus receive information from?
Definition
From each eye
Term
What synthesizes clock proteins?
Definition
Self-starting genes of SCN neurons
Term
What is responsible for synchronizing the biological clock with the environment
Definition
Melatonin released from the pineal gland
Term
When does melatonin secretion occur?
Definition
During periods of darkness
Term
What is another name for the pituitary gland?
Definition
Hypophysis
Term
The adenohypophysis is another name for what part of the body?
Definition
Anterior pituitary
Term
The neurohypophysis is another name for what part of the body?
Definition
Posterior pituitary
Term
What are the two types of neurosecretory neurons?
Definition
Supraoptic nucleus (SON)

Paraventricular nucleus (PVN)
Term
Specifically, what cell bodies produce oxytocin and vasopressin?
Definition
Neurosecretory neuronal cell bodies of the hypothalamus
Term
Specifically, where is oxytocin and vasopression released into systemic blood at?
Definition
Neuronal terminals of the posterior pituitary gland
Term
True or False:

Supraoptic nuclei and Paraventricular nuclei can both produce vasopressin and oxytocin
Definition
True
Term
What is the major factor in the release of ADH?
Definition
Hypothalamic osmoreceptors
Term
What effect does ADH have on arteriolar smooth muscle?
Definition
Vasoconstriction
Term
What are the two ways in which oxytocin is released?
Definition
Stimulation of cervical mechanoreceptors

Stimulation of nipple mechanoreceptors
Term
Why role does oxytocin have at the breasts?
Definition
Increases myoepithelial tone
Term
What role does oxytocin have at the uterus?
Definition
lowers threshold potential
Term
What are the two categories of hypophysiotropic hormones? Functions?
Definition
Hypothalamic releasing hormone - stimulates release of hormone from anterior pituitary cells

Hypothalamic inhibiting hormones - inhibits release of hormone from anterior pituitary cells
Term
What is the name for the direct link from the hypothalamus to the pituitary?
Definition
Hypothalamic-hypophyseal portal system
Term
What is the location where the neurosecretory neurons terminate?
Definition
Capillaries of the hypothalamic-hypophyseal portal system
Term
True or False:

The hypothalamus is protected by the blood brain barrier
Definition
False
Term
What effect does prolactin have on men?
Definition
Production of luetenizing hormone receptors
Term
What are the three major effects of growth hormone?
Definition
Net synthesis of proteins
Increase length of long bones
Increase number of cells in soft tissues
Term
True or False:

Growth hormone is continuously secreted
Definition
False
Term
What influences fetal growth?
Definition
Placental hormones
Term
What two hormones contribute to the cessation of bone growth at the end of puberty?
Definition
T and E2
Term
What is the most abundant anterior pituitary hormone secreted?
Definition
Growth hormone
Term
Describe the binding of growth hormone.
Definition
G.H. binds directly to target tissue
Term
What effect does G.H. have on adipose tissue?
Definition
Breaks down triglycerides to increase blood fatty acids
Term
True or False:

Growth hormone plays a role in increasing blood glucose
Definition
True
Term
True or False:

Growth hormone directly exerts growth-related effects
Definition
False

Growth-related effects are mediated by insulin-like growth factors
Term
What is the function of IGF-1?
Definition
Mediate growth hormone's growth-promoting actions
Term
Where does IGF-1 come from?
Definition
Liver
Term
What affect can malnutrition have of IGF-1?
Definition
lowers IGF-1 but increases G.H.
Term
True or False:

FSH/LH and sex steroids all stimulate IGF-1 secretion
Definition
true
Term
True or False:

IGF-II is influenced by G.H. just like IGF-I
Definition
False

IGF-II is not influenced by G.H.
Term
What is the role of IGF-II during adulthood?
Definition
Unknown, but it is secreted
Term
What is the primary role of IGF-II?
Definition
Stimulate placental growth and pre/post implantation embryonic growth
Term
What two ways does growth hormone, through IGF-1, stimulate growth in soft tissues?
Definition
Hyperplasia - increases cell division, reduces apoptosis

Hypertrophy - increases protein synthesis, reduced protein degradation
Term
What do osteoblasts need to form bones?
Definition
The secretion of osteoid
Term
What is responsible for the tensile strength of bone?
Definition
Osteoid
Term
What is osteoid?
Definition
Extracellular matrix composed of collagen and semisolid gel
Term
What is responsible for the resistance to compression in bones?
Definition
CaPO4 precipitation and bone hardening
Term
What is the connective tissue surrounding bone?
Definition
Periosteum
Term
What is diaphysis?
Definition
Shaft of the long bone
Term
Bone marrow is contained within what part of the bone?
Definition
Diaphysis
Term
What part of the bone is known as the knobs at either end where articulations form?
Definition
Epiphysis
Term
What is the epiphyseal plate of the bone?
Definition
cartilaginous growth region between diaphysis and epiphysis
Term
What is the role of osteoclasts during intramembraneous ossification and appositional growth?
Definition
remove bone to enlarge marrow cavity
Term
What type of ossification is responsible for thickness?
Definition
intramembraneous ossification
Term
Endochondral ossification is responsible for ______
Definition
Length
Term
During endochondral ossification, what happens to the hyaline cartilage?
Definition
replaced with bone tissue
Term
What role do chondrocytes play in the widening of epiphyseal plates?
Definition
Chrondrocytes along epiphyseal plate multiply

Chrondrocytes next to diaphysis hypertrophy
Term
What is the function of chrondrocytes, osteoclasts, and osteoblasts during the calcification of hypertophied cartilage?
Definition
Chrondrocytes - either burst or lack access to nutrients

Osteoclasts - clear away dead cells and calcified matrix

Osteoblasts - move in and build bone tissue
Term
When osteoblasts become entrapped by secreted matrix, what do they turn into? How do the trapped osteoblasts receive nutrients?
Definition
Turn into osteocytes

Nutrients delivered via canaliculi (tiny canals)
Term
How do osteocytes exchange calcium between bone and blood?
Definition
Under the control of parathyroid hormone
Term
What affect does growth hormone/IGF-1 have on osteoblast activity?
Definition
Increases it
Term
GH/IGF-1 increases proliferation of __________________________
Definition
epiphyseal articular cartilage
Term
What has the ability to cause complete ossification of bones?
Definition
Rising sex hormones
Term
Exercise, stress, and decreased glucose have what effect on GH secretion?
Definition
They increase GH secretion
Term
What affect does a high protein meal play with growth hormone?
Definition
It will increase growth hormone with the goal of protein synthesis
Term
If blood fatty acid level fall, how does GH eventually stabilize it?
Definition
GH will be stimulated which will mobilize fats and stabilize blood fatty acid levels
Term
True or False:

Growth hormone level s are similar during periods of accelerated growth as in normal adults
Definition
True
Term
What causes a primary growth defect?
Definition
Pituitary defect
Term
What causes a secondary growth defect?
Definition
Hypothalamic dysfunction by lacking GHRH
Term
The primary cause of growth hormone excess is...
Definition
Pituitary tumor of somatotropes
Term
If a pituitary tumor were to occur duirng childhood, what would occur?
Definition
Rapid growh in height without distortion of body proportions
Term
Acromegaly can only occur after what event?
Definition
Closure of epiphyseal plate
Term
What role does insulin play in growth?
Definition
Promotes protein synthesis
Term
True or False:

Androgens involved in growth are permissive.
Definition
False

Androgens are synergistic
Term
How do androgens help to stop growth?
Definition
By promoting the closure of epiphyseal plates
Term
What role doe estrogens play in the stunting of growth?
Definition
Same as androgens, by promoting the closure of epiphyseal plates
Term
What programs the brain for masculine GH secretion patterns?
Definition
Androgens
Term
Describe the anatomy of the thyroid? Location?
Definition
Bilateral lobes connected by isthmus

Anterior to trachea, inferior to larynx
Term
What are the two major types of cells of the thyroid?
Definition
1) Follicular cells
2) C Cells (parafollicular cells)
Term
Follicular cells form _________ which are filled with ________.
Definition
follicles, colloid
Term
Which type of thyroid cells are responsible for the formation of thyroid hormone?
Definition
follicular cells
Term
What type of cells produces the glycoprotein, thyroglobulin?
Definition
follicular cells
Term
What type of cell secretes calcitonin?
Definition
C cells of the thyroid
Term
What is the function of C cells?
Definition
calcium homeostasis NOT metabolism
Term
True or False:

C cells play an important role in metabolism.
Definition
False
Term
What are the 4 requirements for thyroid hormone synthesis?
Definition
Iodide, tyrosine, thyroglobulin, and thyroperoxidase (TPO)
Term
Describe the one requirement of ALL reactions used to synthesize thyroid hormones?
Definition
All reactions occur with tyrosine molecules that are incorporated into thyroglobulin by peptide bonds.
Term
What two things need to occur during the secretion of thyroid hormone?
Definition
1) Separate t3 and t4 from Tg
2) Move t3 and t4 from the lumen to the blood
Term
True or False:

T4 is the main form of thyroid hormone released from the thyroid
Definition
True

roughly 90% is t4
Term
The primary locations where t4 converts to t3 are?
Definition
Kidneys and liver
Term
T4 and T3 are bound to what during circulation?
Definition
Thyroxine-binding globulin (TBG)
Term
True or False:

T4 is 10x more potent than T3
Definition
False

other way around
Term
True or False:

Every cell has thyroid hormone receptors. Therefore thyroid hormones effect all tissues of the body.
Definition
True
Term
True or False:

Thyroid hormones effects occur relatively quickly.
Definition
False

Effects occur slowly, over several days
Term
What is the biologically active form of thyroid hormone?
Definition
T3
Term
What effect does thyroid hormone have in respect to catecholamines?
Definition
Thyroid hormone raises target cell responsiveness to catecholamines
Term
What metabolic processes are present when T3 is high? Low?
Definition
Glycogenolysis, lipolysis

Glycogenesis, lipogenesis
Term
True or False:

An increase in Thyroid hormone decreases basal metabolic rate
Definition
False

increases
Term
What is the calorigenic effect?
Definition
Increased metabolism leads to an increased heat production
Term
What is the relationship between thyroid hormone and neonates?
Definition
T3 levels are critical for development and effects of low t3 are irreversible
Term
What is the primary site for negative feedback of the thyroid gland?
Definition
Anterior pituitary
Term
What effect does thyrotropin-releasing hormone have on the anterior pituitary?
Definition
Stimulated the A.P.
Term
What effect does physical stress, starvation, and infection play on the hypothalamus? What about the cold?
Definition
Inhibits hypothalamus

Stimulates hypothalamus
Term
What is cretinism?
Definition
Hypothyroidism from birth resulting in mental retardation and dwarfism.

Mental retardation can be prevented with immediate replacement therapy
Term
What are the causes of secondary hypothyroidism?
Definition
Deficiency of TRH, TSH, or both
Term
What term refers to carbohydrate infiltration in the skin?
Definition
Myxedema
Term
What is exophthalmos?
Definition
Edema caused by carbohydrate buildup behind eyes

Specific to graves disease
Term
An example of an interconversion is gluco_______
Definition
gluconeogenesis
Term
How long can adipose provide the body with energy?
Definition
roughly 2 months
Term
What are excess amino acids converted into?
Definition
Glucose then to triglycerides
Term
If fasting, how long does it take to break down the livers glycogen store?
Definition
12 hours or less
Term
What does the term glucose sparing refer to?
Definition
ensuring there is enough glucose to supply the brain
Term
True or False:

During the absorptive state, fats and amino acids are a large source for fuel
Definition
False:

Very little fat and amino acids used for fuel
Term
Which functional metabolic state does gluconeogenesis occur? Glucose sparing?
Definition
Both during postabsorptive phase
Term
What happens to glucose during the absorptive phase? Postabsorptive phase?
Definition
Absorptive - converted and stored as triglyceride

Post - production of new glucose through gluconeogenesis
Term
What organ functions as the primary blood glucose controller?
Definition
Liver
Term
What organ converts glycerol to glucose?
Definition
Liver
Term
Lactic acid is converted into ______ by the ___________
Definition
glucose, liver
Term
What is the major reason for death as a result of starvation?
Definition
Protein wasting
Term
Which cells of the pancreas secrete pancreatic polypeptide?
Definition
F-cells
Term
True or False:

One function of insulin is to inhibit glycogenolysis
Definition
True

This helps favor the storage of glycogen effectively lowering blood glucose and keeping it lower
Term
How does insulin inhibit gluconeogenesis?
Definition
By decreasing the amino acid concentration within the blood and inhibiting certain enzymes
Term
What are the two functions of glucose phosphorylation?
Definition
Keeps glucose trapped inside cells
Keeps intracellular glucose concentrations low
Term
Which glucose transporter is sensitive to insulin?
Definition
GLUT-4
Term
What areas of the body does GLUT-2 work within?
Definition
B-islet, kidney, liver, and intestinal cells
Term
True or False:

GLUT-1 is responsible for the blood brain barrier.
Definition
True
Term
When GLUT-4 is not needed, what occurs?
Definition
Endocytosis of GLUT-4 which returns GLUT-4 vesicle to the intracellular pool
Term
Describe the dependency of insulin in regards to skeletal muscle cells.
Definition
At rest, skeletal muscle cells are dependent upon insulin.

During exercise, skeletal muscle cells are not dependent upon insulin because muscular contractions trigger insertion of GLUT-4
Term
Describe the brain's dependency on insulin.
Definition
The brain is not dependent upon insulin since it is freely permeable to glucose as a result of GLUT-1 and GLUT-3
Term
Describe the liver's dependency upon insulin.
Definition
The liver is not dependent upon insulin because it does NOT use GLUT-4. However, the presence of insulin does enhance carbohydrate metabolism, effectively stimulating glucose phosphorylation
Term
True or False:

Insulin has a catabolic effect on proteins.
Definition
False

Anabolic effect
Term
When exciting insulin secretion, glucose enters the B-islet via which GLUT?
Definition
GLUT-2
Term
Once glucose enters B-islet, what occurs?
Definition
Phosphorylation by glucokinase which is ATP dependent
Term
When G6P is oxidized within the B-islet, what is produced? What is the function of this product?
Definition
ATP which functions to close K+ channels leading to an increase in intracellular K+
Term
During insulin secretion, how does membrane depolarization occur?
Definition
Volatage gated Ca++ channels open leading to an influx of Ca++
Term
What function does Ca++ play during insulin secretion?
Definition
Ca++ mobilizes insulin vesicles and allows them to fuse to the membrane allowing insulin to secrete into the bloodstream via exocytosis
Term
What effect does autonomic stimulation play in regards to the secretion of insulin?
Definition
Stimulates insulin secretion be innervation the B-islets
Term
What is another name for G.I. hormones?
Definition
Incretins
Term
What is the correlation between glucagon and glucose levels?
Definition
Direct correlation
Term
True or False:

Increase amino acids will increase a-islet and decrease b-islet activity
Definition
False

increases both
Term
An increase in growth hormone will have what effect on blood glucose?
Definition
Antagonize glucose uptake by muscles leading to glucose sparing
Term
True or False:

Cortisol decreases glucose uptake by tissues other than the brain
Definition
True
Term
What is the effect of epinephrine on amino acids and muscle protein?
Definition
NONE
Term
Insulin dependent diabetes is also known as...
Definition
Type I diabetes mellitus
Term
True or False:

Gestational diabetes correlates with Type II diabetes later in life.
Definition
True
Term
T-lymphocyte destruction of B-cells correlates with which form of diabetes?
Definition
Type I
Term
What effect do fatty acids have on B-cells?
Definition
Cause apoptosis
Term
What is the effect of incretin mimetics?
Definition
Enhances feed-forward effect
Term
What type of hormones are secreted from the adrenal cortex? What are the three specific ones?
Definition
Steroids

Mineralcorticoids
Glucocorticoids
Sex Steroids
Term
What is the outer layer of the adrenal cortex referred to as? Which hormones are secreted from this location
Definition
Zona glomerulosa

Secretes mineralcorticoids specifically aldosterone
Term
What is the middle layer of the adrenal cortex referred to as? What hormones are secreted from this location?
Definition
Zone fasciculata

Secretes glucocorticoids specifically cortisol
Term
The inner layer of the adrenal cortex is referred to as ______________? This area secretes which hormones?
Definition
Zona reticularis

Secretes sex steroids specifically DHEA and some cortisol
Term
Which hormone is the most abundant adrenal androgen?
Definition
DHEA
Term
What are the three functions of DHEA?
Definition
Growth of pubic/auxillary hair
Pubertal growth spurt
Female sex drive
Term
What hormone is effected by the negative control of DHEA?
Definition
GnRH NOT CRH
Term
Describe the output of cortisol versus DHEA?
Definition
Their output is parallel
Term
What is the physiological significance of aldosterone?
Definition
Important for controlling blood volume and pressure
Term
What is the function of aldosterone?
Definition
Promotes Na+ retention and K+ excretion during hypovolemia
Term
What is the effect of high aldosterone?
Definition
High blood volume leading to HBP leading to increased potassium loss leading to paralysis/muscle weakness
Term
Describe the renin-angiotensin system pathway.
Definition
Angiotensinogen + Renin leads to angiotensin I. ATI plus ACE leads to angiotensin II. Angiotensin II tells the adrenal cortex to make aldosterone.
Term
Which hormone is of most importance during prolonged fasting?
Definition
Cortisol
Term
True or False:

Cortisol decreases the muscle and liver response to insulin
Definition
True
Term
How is the negative feedback control of cortisol overridden?
Definition
Stress
Term
What disorder is known as primary hyperaldosteronism?
Definition
Conn's syndrome
Term
What is the major cause for secondary hyperaldosteronism?
Definition
High activity of the renin-angiotensin system
Term
Epinephrine and norepinephrine is secreted from...
Definition
adrenal medulla
Term
True or False:

The adrenal medulla is a modified component of the parasympathetic nervous system.
Definition
False

sympathetic system
Term
In regards to the adrenal medulla, how could one describe the nerve tract leading to the medulla.
Definition
Consists of preganglionic fibers which terminate on chromaffin cells
Term
What type of cells within the adrenal medulla release catecholamines?
Definition
Chromaffin cells
Term
Where are catecholamines produces within the adrenal medulla?
Definition
Cytosol
Term
What are the names/functions of the 4 adrenergic receptors?
Definition
a1 - constrict blood vessels
a2 - dilate pupils, inhibit insulin
b1 - increase heart rate
b2 - dilate blood vessels, bronchodilation
Term
True or False:

The binding of NE to B2 promotes the breakdown of glycogen in muscle.
Definition
False

E instead of NE
Term
What is the general effect of epinephrine only versus epinephrine and the sns?
Definition
E only - decreases resistance to ventilation

E and SNS - mobilizes body resources to support peak physical exertion
Term
Approximately what percent of Ca++ is in the skeleton/teeth? ICF? ECF?
Definition
99%, 0.9%, 0.1%
Term
What % of PO43- is in the skeleton/teeth? ICF? ECF?
Definition
86%, 13.07%, 0.03%
Term
What is the relationship between calcium permeability/concentration and exocytosis?
Definition
Directly proportional relationship
Term
What role does calcium play with blood clotting?
Definition
Cofactor in clotting cascade
Term
An increased in ECF Ca++ leads to... while an increase in cytosolic Ca++ leads to...
Definition
Suppression

Contraction
Term
What is the principal regulator of Ca++ and PO43-?
Definition
parathyroid hormone
Term
True or False:

Calcium balance is an immediate, minute-to-minute adjustment.
Definition
False

This described Ca++ homeostasis
Term
What does the secretion of parathyroid hormone prevent?
Definition
Hypocalcemia
Term
What would happen if no parathyroid hormone was present?
Definition
Spasm of respiratory hormone leading to asphyxiation
Term
Where are osteoblasts differentiated from? Osteoclasts?
Definition
Bone marrow stromal cells

Macrophages
Term
How do osteoclasts bring about resorption?
Definition
Secrete HCl that dissolves precipitate and secretes an enzyme that digests matrix
Term
What determines bone density?
Definition
Ratio of RANKL and OPG
Term
Ostesprotegerin (OPG) binds with _________ and prevents __________________
Definition
RANKL, resorption by promoting apoptosis in osteoclasts
Term
True or False:

Mechanical stress favors the increase in bone mass and strength.
Definition
True
Term
What role does PTH play in reference to Ca++?
Definition
Ca++ efflux into plasma
Term
How does Vitamin D work to increase Ca++ absorption?
Definition
Just like a protein would elicit an effect. By doing so it increases the responsiveness of bone to PTH
Term
What is the main difference between fast and slow movement of Ca++?
Definition
Fast - no PO43-

Slow - PO43- moves with Ca++
Term
What are the two effects of calcitonin on bone?
Definition
Decreases Ca++ movement from bone fluid to plasma

Decreases bone resorption
Term
How does Calcitonin inhibit osteoclasts?
Definition
via cAMP pathway
Term
What occurs as a result of an increase in vitamin D and an increase in urinary excretion of Ca++?
Definition
The effects counteract each other resulting in No change in plasma Ca++
Term
How does the body maintain Ca++ levels if there is a vitamin D deficiency?
Definition
By using the bones Ca++ (Not good)
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