Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FOE > Endo Physio Chap 1 > Flashcards

Endo Physio Chap 1 Flashcards

1
Q

What is neuroendoccine hormones?

A

Hormones secreted by neurons and through the blood acts on different target ell in different location

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are paracrine and autocrine hormones?

A

Paracrine → secreted to extracenular fluid and acts on neighbouring cells
Autocrine → secreted to extracellular fluid and acts on the same cell from which they are produced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are hypophysiotropic hormones?

A

They are secreted from hypothalamus and controls the secretion of anterior pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are proteins and peptic hormones formed in cell?

A

In RER → formed as pre- prohormone → converted to pro-hormone in ER → and then packed into vesicles in Golgi
Apparatus → converted to hormone (active) in vesicle by enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two stimuli for release of protein or peptic hormones?

A
  1. Increase in cytosolic calcium level due to depolarization of cell
  2. Stimulation of cells receptors which increase cAMP which in turn activates protein kinase which causes release of hormone by exocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are steroid hormones made from and what is their structure?

A

They are synthesised from cholesterol
They have 3 cyclohexyl rings and 1 cyclopentyl sing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Are steroid hormones premade and stored in cells ?

A

No → steroid hormones are not stored → when stimulus appears they are synthesised at that time from already stored cholesterol esters in cytoplasm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Are thyroid hormones stored individually or attached to protein in thyroid gland?

A

Thyroid hormones are attached to proteins → thyroglobulin in thyroid gland
They are also attached to thyroxine binding globulin in blood when released from thyroid gland.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How are catcholamines secreted from adrenal medulla?

A

It is stored in vesicles and secreted from the calls through exocytosis
Adrenal medulla produces four times more epinephrine than norepinephrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the different positions for different hormones in cell?

A

1.in or on cell membrane → protein and peptides hormones
2.in cytoplasm → steroid hormones
3.in nucleus → thyroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Are the number of receptor for hormones always constant?

A

No the number -. - - and sensitivity of receptors changes from day to day or even from minute to minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the factors that causes down-regulation of receptors?

A
  1. Inactivation of receptor molecules
  2. Inactivation of second messenger singling proteins
  3. Inward pull of receptors
  4. Degradation of receptor by lysosomes
  5. Decrease production of receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What factors causes up-regulation of receptors?

A
  1. Increase formation of receptors or second messenger proteins
  2. Availability of receptor for hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are ion-channal linked receptors?

A

These are receptors that when attached to hormone undergo structure change by opening or closing of a channel for one or more ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are two mechanisms through which ion-channel linked receptors work?

A
  1. Direct mechanism → hormone attaching directly to the ion channel and opens or closes the channel
  2. Indirect mechanism → ion-channels are opened through the g-protein or enzyme-linked channels.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of receptors are present in g-protein coupled receptors?

A

They are usually multipass transmembrane receptors
The cytoplasmic tail is coupled with g-protein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the structure of g-protein.?

A

It has three subunits → alpha, beta and gamma
The alpha subunit is attached to GDP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What three functions maybe performed by g-protein after it is activated ?,

A
  1. Open or close an ion channel.
  2. Change activity of an enzyme. ( such as adenylyl cyclase and phospholipase C )
  3. Activate gene transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is the signaling function of g-protein terminated?

A

, When the hormone is removed from receptors the alpha subunit converts GTP to GDP and becomes attaché to beta and gamma subunits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the two types of g-proteins?

A
  1. Inhibitory g-proteins
  2. Stimulator g-protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are enzyme-linked receptors?

A

The receptors when binds to hormones causes activation of nearby enzymes or transforms to enzyme itself ( have intrinsic enzymatic activity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of transmembrane proteins are used as enzyme. Linked receptors.?

A

One pass or single-pass transmembrane proteins

23
Q

Name some hormones that uses tyrosine kinase for en signaling?

A

I. Gh
2. Insulin
3. Insulin like growth factor - 1
4. Leptin
5. Fibroblast growth factor
6.Prolactin
7. Vascular endothelia growth factor
8. Hepartocyte growth factor.

24
Q

In case of leptin which family of tyrosine kinase is used in signaling pathway?

A

Janus kinase ( JAK ) family ( jak-2 )

25
Q

What are second messengers?

A

Some hormones can’t cause intraullular changes itself so other molecules causes these affects after
Activated by the hormone eg camp → these substances or molecules are called second messengers.

26
Q

What are some hormones that uses intracellular hormone receptors?

A
  1. Adrenal and gonadal steroid hormones
  2. Retinoid hormones
  3. Thyroid hormones ( intranuclear receptors )
  4. Vitamin D
27
Q

What is hormone response element?

A

, It is a specific regulatory sequence of DNA with which the hormone - receptor complex attaches and in this way activates or represses transcription of gene.

28
Q

Would all the tissues have same response to a hormone if they have same intracellular receptors for that hormone?

A

No → because an intracellular receptor can activate a gene only it an appropriate combination of gene regulatory proteins are present and some of these proteins are tissue specific
So,,, The response of different tissues to a hormone are determined not only by receptor specificity but also by expression of gene.

29
Q

What are the three important second messengers?

A

1.cAMP
2. Breakdown products of membrane phospholipids
3. Calcium ions and associated calmodulin

30
Q

What is the mechanism of adenylyl cyclase - camp system?

A

Hormone attaches to g-protein linked receptor → g-protein stimulates adenylyl cyclase → changes ATP to camp → camp attaches with camp dependent protein kinase→ it phosphorylates the cell proteins and generates a response

31
Q

What is adenylyl cyclase ?

A

It is a cell membrane - bound enzyme that converts ATP to camp

32
Q

What does the specific action in response to camp in each target cell depends on with examples ?

A

It depends on intracellular machinery of each target cell
For example # camp causes
1. Production of metabolic enzymes ( thyroxine and triiodothyronine ) in thyroid cell
2. Production of steroid hormones in adrenal cortex cells
3. Increase permeability of DCT and connecting ducts in kidney cell

33
Q

Mechanism of the phospholipids second messenger system?

A

Hormone attaches to the receptor , it activates the phospholipase C enzyme in the cell membrane → which breaks down phosphotidylinsitol triphosphate → insitol biphosphate and diacylglyceral

  1. Insitol biphosphate → releases calcium from mitochondria and endoplasmic reticulum→ calcium acts as
    Second messenger and causes response of cell such as smooth muscle contraction and cell secretions
  2. Diacylglycerol → activates protein kinase C→ inturn phosphorylates other proteins and causes response → diacylglycerol also have arachidonic acid which is a precursor of prostaglandin and other hormones
34
Q

Mechanism of calcium - calmodulin second messenger?

A

Calcium enters cell → attaches to calmodulin ( three or four calcium per calmodulin )→ calmodulin activates protein kinase → which phosphorylates proteins and generate response
For example # calmodulin activates myosin light chain kinase → which causes contraction of smooth muscles

35
Q

What is the normal value of calcium inside cell and how much is needed for calmodulin system to activate?

A

Normal value of calcium in cell is 10-8 to 10-7 mol/L
Calcium required for calmodulin to activate is 10-6 to 10-5 mol/L

36
Q

What are the two main types of hormones that acts mainly on the genetic machinery of cell?

A

Steroid hormones → increases protein synthesis
Thyroid hormones → increases gene transcription

37
Q

What is the mechanism for steroid hormones to increase protein synthesis?

A
  1. Steroid hormone enters the cell
  2. Attaches to the specific receptor in cytoplasm
  3. Goes to nucleus
  4. Attaches to specific sequence of DNA ( receptor response element)
  5. Causes transcription of specific gene to form mRNA and eventually proteins
38
Q

What is the receptor for aldosterone called?

A

Mineralocorticoid receptor

39
Q

How much time it takes for aldosterone to make proteins once it enters the cell?

A

45 minutes for proteins to appear

40
Q

Where does thyroid hormones binds with its receptor?

A

Inside nucleus ( intranuclear receptors ) on the chromosome complex

41
Q

What are the two main functions of thyroid hormones inside nucleus?

A
  1. Activate genetic machinery to form proteins which enhance the metabolic function of cells.
  2. Once bound these hormones can work for days or even weeks
42
Q

What concentration of a hormone is needed for its action?

A

Very little from 1 picogram to a few microgram per mililiter of blood approx

43
Q

What are the variables that control the secretion of hormone or causes negative feedback?

A
  1. Hormone itself
  2. One of its product
  3. Sometimes Degree of activity of target cell rather than its rate of secretion
44
Q

Does positive feedback occurs in hormones?

A

Yes, it causes surges of hormones e.g estrogen -LH

45
Q

What is the most powerful or superimposed mechanism for control of hormones secretions?

A

Cyclical variation / periodic variations such as seasonal changes, stages of development, aging etc.

46
Q

Why does cyclical variations in hormones secretions occur?

A

Due to changes in activity of neuronal pathways. Involved in controlling hormones secretions.

47
Q

What are the two ways through which hormones are transported through blood?

A
  1. Dissolved in plasma → water soluble hormones such as proteins, peptides and catcholamines
  2. Bound to proteins → steroids and thyroid hormones → 10% usually exist free in blood
48
Q

How does hormones bound to proteins in blood acts as hormone reservoir?

A

Because they replenish the concentration of free hormone when they are bound to target. Cell or lost in circulation

49
Q

What is metabolic Clarence rate?

A

Number of mibiliters of plasma cleared from hormone per minute.

50
Q

What is formula for metabolic clearance rate?

A

= rate of disappearance of hormone from plasma / concentration of hormone in plasma

51
Q

What are the 4 ways in which hormones are cleared from plasma?

A
  1. Metabolic destruction by tissue → target cell causes endocytosis of hormone - receptor complex→ hormone is metabilized
  2. Binding with tissue
  3. Excretion by liver into bile
  4. Excretion by kidney into urine. → mostly water-soluble hormones are degraded in the blood and excreted through kidney and liver
52
Q

Which hormones are more easily cleared from blood, water-soluble or protein-bound?

A

Water soluble are easily cleared from plasma than protein bound.
For example # half life of
Angiotensin 2→ less than a minute
Adrenal steroids → 20 to 100 minutes
Thyroid hormones → 1 to 6 days

53
Q

What is the enzyme caned that cleaves or eats camp to terminate the reaction?

A

Phosphodiesterase ( it also work for phospholipase C )

FOE (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions