Exam 1 Q Doc Flashcards
(70 cards)
1
Q
Describe endocrine glands in terms of duct, secretion, and destination?
A
Endocrine glands are ductless, release secretory products into the interstitial fluid, and their secretions diffuse into blood which are transported to distant targets.
2
Q
Describe exocrine glands in terms of duct, secretion, and destination?
A
Exocrine glands possess transporting ducts that connect to target cells, secrete products into a duct, and their secretions exit the body or enter the lumen of another organ.
3
Q
The endocrine system differs from other systems in four main ways. Name them
A
- Endocrine glands, tissues, cells are not anatomically connected. They form a system in the functional sense.
- Tissues and cells can be diffuse, for example, white blood cells, fat (adipose) cells.
- Some are temporary, for example, placenta, thymus.
- Some endocrine organs have other functions, for example kidney secretes hormone erythropoietin.
4
Q
The four basic cell types are
A
muscle, nerve, epithelial, connective
5
Q
Neuroendocrine signaling
A
a type of classic endocrine signaling that is synthesized by neural cells, released into the blood, then reaches target ‘at a distance’.
6
Q
Paracrine signaling
A
a type of non-classic local cell signaling that affects adjacent cells.
7
Q
Autocrine signaling
A
a type of non-classic local signaling in which the signal must exit the cell into the extracellular matrix to then have an effect on the same cell.
8
Q
In 1921, Otto Leowi demonstrated neurons transmit using a chemical messenger. Describe the conclusion from Loewi’s experiment.
A
- After stimulation, the vagus nerve of the isolated heart releases acetylcholine on cardiac muscle (also releases acetylcholine into the media), which causes relaxation of cardiac muscle contraction.
- Heart rate (also cardiac muscle contraction) is under neural regulation via neurotransmitters released from nerve terminals.
9
Q
homeostasis
A
the ability to maintain internal milieu (environment) at a fairly constant level.
10
Q
Our total body water is comprised of…
A
Plasma, interstitial fluid, intracellular fluid
11
Q
Is there a set point for any physiological variable invariant? Explain.
A
- Not a point, but a range.
- Depends on time of day and year, stage of development, age, reproductive status, long term exercise/disease condition (e.g. fever) of an individual.
12
Q
What are the afferent and efferent pathways and integrating center?
A
- Afferent and efferent pathways: nerves and hormones (inputs and outputs are neural and hormonal signals).
- Integrating center: the central nervous system.
13
Q
Homeostasis refers to the ______ mechanisms that detect and respond to deviations in physiological variables from their “_____ _____” values, by initiating effector responses that restore the variables to the optimal physiological range.
A
dynamic / set point
14
Q
Describe a negative feedback mechanism.
A
If body temperature increases, to cool down the body will produce sweat as a cooling mechanism and eventually the body will cool down.
15
Q
_____ is responsible for increasing blood-glucose levels and ______ is responsible for lowering blood-glucose levels.
A
Glucagon, insulin
Effects of glucagon: increase blood glucose levels
Effects of insulin: lower blood glucose levels
16
Q
Feedforward regulation initiates an adaptive response ______ the variable is being changed.
A
before
17
Q
When there is an increase of Ca2+ in the blood, the thyroid will release ________, whereas when there is a decrease of Ca2+ in the blood, the parathyroid will release ______.
A
Calcitonin
Parathyroid Hormone (PTH)
18
Q
Angiotensin II works on the cardiovascular system and the kidneys simultaneously to ______ blood pressure. Angiotensin II causes blood vessels to _______ and adrenal cortex to release aldosterone. Aldosterone works on the kidneys to ______ salt and water.
A
increase
constrict
reabsorb/retain
19
Q
_____ is a hormone responsible for Na+ excretion, which lowers blood pressure.
A
Atrial natriuretic peptide (ANP)
20
Q
Amine hormones are derived from the amino acid _____.
A
tyrosine
21
Q
What are the three general structural classes of hormones?
A
Peptide hormones
amino acid-derived hormones
Lipid-derived hormones
22
Q
Describe the action mechanism of lipid soluble hormones.
A
- Typically travel in the blood bound to a carrier protein
Permit passive diffusion through plasma and nuclear membranes
Typically interact with a cytosolic or nuclear receptor - Hormone binding to receptor changes conformation of receptor - inhibitory protein(heat shock protein, HSP) dissociates and LBD of receptor binds to ligand. LBD of receptor also binds to coactivator proteins; DBD of receptor interacts with DNA, binds to hormone responsive element (HRE) of DNA with zinc finger - genomic effects.
23
Q
Describe the action mechanism of water soluble hormones.
A
- Travel freely in the blood
Do not passively permeate cells by diffusion through plasma membrane
They typically interact with cell surface membrane receptors, then coupled to activation of intracellular signal transduction pathways - Reversible protein phosphorylation and signal amplification (most time using 2nd messengers).
24
Q
Describe the process of neurotransmitter release:
A
- Action potential reaches terminal
- Volted gated Ca2+ channels open
- Calcium enters axon terminal
- Neurotransmitter is released and diffuses into the cleft
- Neurotransmitter binds to postsynaptic receptors
- Neurotransmitter removed from synaptic cleft by reuptake, degradation, or diffuses away
25
Hormone binding globulins have four main functions. Name those functions:
- Globulins transport hormones
increasing solubility of hormones in blood
- Regulate bioavailability of hormones
since bound hormone cannot enter cells and have physiological action
- Regulate metabolic clearance of hormones
since bound hormone can not enter liver/kidney cells
for degradation and excretion
- Storage of hormone
provide readily available store of hormone
carrier proteins extend the half-life of a hormone
26
One of stimuli that stimulates growth hormone release is increase in plasma ___________
Amino acids
27
Regarding metabolism, ______ is the amount of time required for half the molecules to become inactivated or cleared from the circulation.
T1/2 (half life)
28
In Endocrine pathophysiology, over/under production of a hormone is a result of ....
primary or secondary hyper/hyposecretion
29
Describe primary hyper/hyposecretion.
- Primary hyposecretion can be due to gland destruction, decreased hormone synthesis, dietary deficiency (iodine)
If a gland is secreting too little hormone because it itself is unable to function normally, the disorder is called primary hyposecretion.
- Primary hypersecretion results from excess secretion (usually from a tumor)
Primary hypersecretion is a gland itself secreting too much hormone
30
Describe secondary hyper/hyposecretion.
- secondary hyposecretion can be due to too little tropic hormone
- secondary hypersecretion can be due to excessive stimulation by tropic hormone.
31
Oxytocin and vasopressin are related in structure. Both can stimulate uterine smooth muscle contraction and activate renal tubular cAMP production. Describe the affinity for both oxytocin and vasopressin receptors.
- At normal hormone circulating concentrations, each hormone only activates its appropriate target cell receptor.
- Uterine oxytocin receptors have a greater affinity for oxytocin than for vasopressin
- Renal vasopressin receptors have a greater affinity for vasopressin than for oxytocin.
32
Prolactin up-regulating prolactin receptors in liver is an example of ______ regulation.
Homologous
33
How might One single hormone have similar effect on different tissues?
All these different tissues express the same receptor with the same intracellular signaling pathway and effects.
For example: Insulin acts on muscles, the liver and adipose tissue to increase glucose uptake in cells.
34
How might One single hormone have
different effects on different tissues?
All these different tissues express receptor for that single hormone, but coupled to a different intracellular signaling pathway. For example, Parathyroid hormone (PTH) acts on the kidneys to decrease Ca2+ loss. It acts on the bones to increase Ca2+ release.
35
How might Two or more hormones have similar effect on same tissue?
The tissue expresses different specific types of receptors with different kinetics for different hormones (may or may not have similar structures). Both induce the same intracellular effects. For example, Epinephrine and glucagon both act on the liver to stimulate glucose release.
36
Phosphorylation of proteins is completed by ______ whereas dephosphorylation is completed by ______.
Kinases
Phosphatases
37
When a ligand binds to a receptor, the receptor’s shape becomes altered which activates its enzyme function, phosphorylating an intracellular protein. This is known as _______.
Autophosphorylation
38
G proteins bound to _____ are in an active state and proteins bound to ____ are in an inactive state.
GTP
GDP
39
Although G proteins can be smaller in size, all larger G proteins are ______ because each subunit (α, β, γ) is a product of a different gene.
Heterotrimers
40
_______ is an enzyme that increases cellular cAMP and _____ is an enzyme that decreases cellular cAMP.
Adenylate Cyclase
Phosphodiesterase
41
Describe positive feedback. Provide an example.
A stimulus (hormone) activates a response from its target (target cells), and the target cell response triggers further release/activation of the original stimulus.
Ex. Blood clotting, parturition (stretch in cervix triggers hypothalamus to cause release of oxytocin from the posterior pituitary gland. Oxytocin acts on the uterus to cause contractions which increases the stretch in the cervix).
42
The Ras monomeric G protein and the alpha subunit of the heterodimeric G protein both have intrinsic _______ activity to return to an inactive state.
GTPase
43
List two functions that calcium ions are responsible for.
Exocytosis, muscle contraction, activation of T and B cells, apoptosis
44
Ligand ________ are the molecules that bind to the receptor; Ligand ___________ block molecules that bind the receptor
Agonists
Antagonists
45
Positive cooperativity _______ affinity, negative cooperativity _________ affinity
Increases
Decreases
46
Describe Berthold’s experiment and the importance of its results in the field of endocrinology.
Berthold conducted experiments in which he removed testes and replaced them to examine the different effects of castration.
When only one testis was replaced compensatory hypertrophy was observed as negative feedback on pituitary cells took place. Since levels of testicular hormones were lower than average, this led to increased release of FSH and L (pituitary hormones gonadotropins) which made the testis grow to an above average size.
47
Hormones are ________ and ________ by glandular and neurosecretory cells
Synthesized
Secrete
48
Complete the following analogy: Tyrosine: thyroxine:: ______: testosterone
Cholesterol
49
What are permissive effects?
Permissive effects occur when one hormone’s presence and action is required for action of a second hormone. Without the first hormone, the second hormone cannot exert its effects(or very little effect) on its target cell.
Usually the first hormone is a steroid or thyroid hormone that has genomic effects that allow the second hormone to work, like inducing receptor production for the second hormone.
ex: estrogen & progesterone
50
What are synergistic effects?
Synergistic effects are when two hormones work together to produce a marked response on their target cells. The response is larger and more impactful than the additive effects of the two hormones together. Explosive effects.
51
The _____ region of an intracellular receptor protein is responsible for activation and works with a second activation region _____ to regulate (upregulate or downregulate) gene expression, while the _____ binds the (target) hormone responsive element (HRE) of DNA sequence.
AF1 (activation function 1)
AF2 (activation function 2)
DBD (DNA-binding domain)
52
Receptors have many important characteristics: they are highly _____, meaning they respond to one hormone and have a certain effect, and they are very _____, meaning they can change in expression, density, and distribution.
Specific
Dynamic
53
Regarding the synthesis of T3 and T4: Iodine and sodium ions are ______ into the follicular cell together, and the final products move out of the follicular cell through ______ into the interstitial fluid and eventually the bloodstream.
Cotransported
diffusion
54
Melatonin is synthesized from a precursor molecule that is a hormone itself named ______.
serotonin
55
what are the three classes of lipid-derived hormones.
Steroid hormones
Eicosanoids
Endocannabinoids
56
what are the three classes of amine hormones
Catecholamines
Thyroid hormones
Indolamines
57
________ receptors usually have a _____ response because their effects are generally non-genomic, while ______ receptors have a ______ response because their effects are genomic.
Membrane
Fast
Cytosolic/nuclear
Slow
58
Steroid hormones originate from
cholesterol
59
Eicosanoids and endocannabinoids are derived from
arachidonic acid
60
One female rat received a unilateral gonadectomy surgery.
Briefly explain
(1) What is unilateral gonadectomy surgery? (1pt)
(2) What would happen to the remaining gonad? (2 pts)
(3) How do the changes of the remaining gonad happen? (2pts)
(1) Remove only one of two ovaries, the other ovary stays (remains intact).
(2) The remaining ovary undergoes compensatory hypertrophy, with increases in size and number of ovarian cells to compensate functionally for the loss of hormone secretion from the removed ovary.
(3) Compensatory hypertrophy occurs due to partial loss of negative feedback, leads to increased secretion of gonadotropin releasing hormone from the hypothalamus and gonadotropins from the anterior pituitary. Increased level of gonadotropins stimulates the remaining ovary to increase cell number and size.
61
What is the difference between additive and non additive effects of hormones? Know one example.
Non additive effects involve multiple receptors and multiple hormones binding to those receptors, but all receptors trigger a targeted response on only one available secondary protein / use the same pool of proteins or molecules.
Additive effects involve multiple receptors, multiple proteins, and multiple secondary proteins that can receive the signal and amplify it/use different pools of proteins.
62
what determines function
structure
63
____________ is the increase in size of a cell, while _______ is the decrease in the size of a cell
Hypertrophic
Hypotrophic
64
___________ is the increase in the number of cells present in the sample, while ___________ is the decrease in the number of cells present in the sample.
Hyperplasia
Hypoplasia
65
Determine one way in which researchers can label the presence of estrogen recectptor and progesterone receptor proteins in breast tumor tissue sections?
Double labeling immunochemistry (Primary & Secondary Antibodies)
66
____________ labels cells expressing mRNA of nucleic acid sequence (HPV).
In Situ Hybridization (ISH)
67
Immunoblot/Western Blotting allows researchers to analyze the amount of ______.
protein
68
A sample was injected with the radioisotope tritium [3H]-labeled thymidine (autoradiographic method) into the anterior pituitary of rats that had one testicle removed. Describe what the researchers should have observed.
In rats with a testicle removed, the autoradiographic results would have shown a silver color/grains showing mitotic division in the anterior pituitary due to compensatory hypertrophy
69
What type of enzyme could effectively "turn off" a phosphorylation cascade response at the level of enzyme activity?
phosphatase
70
Under high levels of ______ and low levels of ________ Krebs cycle will be inhibited
NADH; ATP
