Brainscape's Knowledge GenomeTM

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


See full index

BIOCHEMISTRY > ME04 - Introduction to Endocrine > Flashcards

ME04 - Introduction to Endocrine Flashcards

1
Q

Local chemical messengers secreted by cells into the ex
tracellular fluid & affect neighboring cells of a different
type

A

Paracrine/Juxtacrine (Histamine)

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

Affects cells of the same type
Secreted by cells into the ECF and affects the function of
the same cells that produced them by binding to cell sur
face receptors

A

Autocrines

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

Peptides secreted by cells into the ECF & can func

tion as autocrines, paracrines or endocrine hormones

A

Cytokines

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

Example of Cytokines

A

a. interleukins & lymphokines ? secreted by
helper cells & act on other cells of the immune system
b. Leptin (adipokines) ? secreted by adipocytes

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

Secreted by neurons into the circulating blood and influ

ence the function of cells at another location in the body

A

Neuroendocrine Hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Example of Neuroendocrine Hormones

A

ADH, OTC, & hypophysiotropic hormones

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

Released by endocrine glands into blood stream & influence function of target cells
Some affect almost all cells & organs (GH, Thyroid hormone, Catecholamines)
Other affect specific tissues (ACTH, TSH, FSH & LH)
Secreted by ductless glands in the endocrine system

A

Endocrine Hormones

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

Function of Endocrine Hormones

A

Play important role in homeostasis

Essential to the maintenance of the life & well being of an individual & of the species

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

Chemical Messengers

Secreted into the blood and acts on another location

A

Hormones

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

Main site of inactivation

A

Liver

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

Mechanism for removal of hormones

A

Kidneys, Liver

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

General Characteristics of Hormones

A
  1. Secreted by specific group of cells
  2. Thrown directly into circulation
  3. Exert effects on target tissues which are distant from the source of hormone
  4. Do not create an additional or new function, only modify or alter functions that already exists.
  5. Rate of secretion fluctuates. Increases when there is a need for it; minimal when need not present.
  6. Do not stay in the circulation forever
    • Can undergo inactivation
    • Main site of inactivation: LIVER
      - Can be removed from circulation through kidneys.
      - Plasma concentration of hormones tested by determining
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Forms of Chemical Signaling

A

Autocrine ? cell targets itself

Signaling across gap junctions ? Cell targets a cell connected by gap junctions

Paracrine ? Cell targets nearby cell

Endocrine ? Cell targets a distant cell through the bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hormones synthesized and secreteed by dedicated Endocrine Glands

A

Pituitary Gland ? GH, Prolactin, ACTH, TSH, FSH, LH

Thyroid Gland ? T4,T3, Calcitonin

Parathyroid Gland ? PTH

Islets of langerhans ? Insulin, Glucagon, Somatostatin

Adrenal Gland ? Epinephrine, NorEpi, Cortisol, Aldosterone, DHEAS

Ovaries ? Estradiol, Progesterone, inhibin

Testes ? Testosterone, AMH, Inhibin

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

Hormones Synthesized in Organs with Primary Function other than Endocrine

A

Brain (Hypothalamus) ? ADH, Vasopressin, Oxytocin, CRH, TRH, GnRH, GHRH, Somatostatin, Dopamine

Brain (Pineal Gland) ? Melatonin

Heart ? ANP

Kidney ? Erythropoietin

Adipose Tissue ? Leptin, Adiponectin

Stomach ? Gastrin, Somatostatin, Ghrelin

Intestines ? Secretin, Cholecystikinin, GLP-1, GLP-2, GIP, Motilin, IGF-1

Liver ? IGF-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Classify Hormones

A
  1. PROTEIN HORMONE
    • More common, Stored in vesicles
  2. BIOGENIC AMINES
    • derivatives of tyrosine
      • thyroid hormones (T3 & T4), adrenal medullary hormones
    • derivative of histidine:
      • histamine (mast cells inconnective tissues)
    • derivatives of tryptophan
      • melatonin (pineal gland)
      • serotonin (blood platelets)
  3. STEROID HORMONE
    • derivative of Cholesterol
    • Synthesized as needed
17
Q

Produces new proteins from DNA
Lipid-soluble
Reflection Coefficient closer to 0

A

STEROID HORMONES

Slow-acting; To produce 2 proteins from DNA

18
Q

Modifies existing proteins
Water-soluble
Reflection Coefficient closer to 1

A

Protein Hormones - facilitates signals; Faster

19
Q

Types of Hormone Receptor

A

G-PROTEIN LINKED HORMONE RECEPTORS
Transmembrane proteins loop in and out of the cell membrane seven times
Make use of G-Proteins

ENZYME-LINKED HORMONE RECEPTORS
Passes through the membranes only once
Makes use of intracellular enzymes directly
E.g. Leptin and its use of Tyrosine Kinase

G Proteins

  • Heterotrimeric GTP-binding Proteins
  • Act as TRANSDUCERS
  • Link hormone receptors with 2nd messenger systems (Intracellular Enzymes and Ion Channels)
20
Q

Intracellular Enzymes and Ion Channels

A

May be Gs Protein (stimulatory) or Gi Proteins (inhibitory)

3 subunits: alpha, beta, gamma

21
Q

The Second-Messenger System

A

? cAMP/cGMP
? IP3/DAG
? Calcium-Calmodulin
? Tyrosine Kinase

22
Q

Most common 2nd Messenger System

A

cAMP/cGMP System

MECHANISM
Alpha subunit of G proteins activates Adenylate cyclase and together with ATP ?>forms cAMP ?> activates protein kinase A

23
Q

Used by all Hypothalamic Hormones EXCEPT CRH

- Mediates smooth muscle contraction by hor-mone/neutrotransmitter (e.g. Motilin in the GI)

A

Phospholipid System (IP3/DAG)

  • MECHANISM
    Phospholipase C ?> PIP2 ?>PIP2 splits into IP3(releases Calcium) and DAG (activates protein kinase C)
24
Q

Used by Insulin, Growth factors, EPO, Leptin

A

Tyrosine Kinase

25
Q

Pathway&raquo_space; G protein&raquo_space; Protein Kinase

A

cAMP&raquo_space; Gs INC cAMP; Gi DEC cAMP; Adenylate Cyclase&raquo_space; Protein Kinase A

IP3/DAG&raquo_space; Gq INC IP3/DAG; Phospholipase C&raquo_space; Protein Kinase C
cGMP&raquo_space;———————-&raquo_space; Protein Kinase G
Tyrosine Kinase&raquo_space; ———-&raquo_space; Tyrosine Kinase/ JAK-STAT
Intracellular (Steroid Hormones)

26
Q

Must be transported bound to a protein in the blood

A

Lipid Soluble Hormones

27
Q

Active form of Lipid Soluble Hormones

A

FREE, UNBOUND FORM

28
Q

What is the Mechanism of Hormonal Action

A

On the target cell, the hormone in combination
with the receptor cells act by any of the following
mechanisms:
1. Alternating the permeability of cell membrane
- Neurotransmitter substances

  1. Activating the intracellular enzyme
    - Protein hormones & catecholamines
  2. Activating the gene
    - Thyroid & steroid hormones
29
Q

Mechanism for Regulation of Hormone Effects

A

MECHANISMS

  • Hormone Secretion
  • Hormone Receptors
30
Q

Differentiate Negative from Positive Feedback

A

NEGATIVE FEEDBACK
?Products inhibit Precursors?
More common
E.g. Cortisol inhibiting ACTH Secretion from the Pituitary

POSITIVE FEEDBACK
?Products stimulate Precursors?
Rare, exploding
E.g. surge of LH before ovulation, Oxytocin during deli-very and lactation

31
Q

Differentiate Down-Regulation from UP-Regulation of Receptors

A 
DOWN-REGULATION OF RECEPTORS
Decrease in:
 - Receptor Number 
 - Receptor Affinity
 - E.g. in the uterus, progesterone down-regulates its own receptor and the receptor for estrogen
UP-REGULATION OF RECEPTORS
Increase in:
 - Receptor Number 
 - Receptor Affinity
 - E.g. in the ovary, estrogen up-regulates its own re-ceptor and that of LH
32
Q

3 types of Hormone Interactions

A

Synergistic Effects | Permissive Effects | Antagonistic Effects

33
Q

Differentiate 2 Types of Synergistic Effec ts (Additive & Complementary)

A
  • ADDITIVE EFFECTS
    • E.g. Epinephrine & NE effects on the heart
  • COMPLEMENTARY EFFECTS
    • E.g. FSH & Testosterone effects on spermatogenesis
34
Q

Differentiate Permissive Effects vs Antagonistic Effects

A

. PERMISSIVE EFFECTS
- E.g. Cortisol has permissive effects on Epi & NE with regards to blood vessels; T3 has permissive effects on Epi with regards to lipolysis

ANTAGONISTIC EFFECTS
- E.g. Estrogen blocking Prolactin effects on the breasts during pregnancy

35
Q

Equal to the rate of disappearance of hormone from the plasma/concentration of hormone in each milliliter of plasma

A

Metabolic Clearance Rate

Mechanisms: Tissue Destruction, Tissue binding, Bile Excretion, Urine Excretion

36
Q

Hormone&raquo_space; Pituitary target

A 
GnRH >> FSH, LH
CRH >> ACTH (B-LPH)
TRH >> TSH (PRL)
GHRH >> Somatotropin (GH)
PRH >> TRH
PIH >> Lactotrophs (PRL)
MRH >> MSH
MIH >> MSH
37
Q

Where Oxytocin is produced

A

Paraventricular nuclei

38
Q

Where ADH is produced

A

Supraoptic nuclei

39
Q

Where hormones are stoed

A

Posterior Pituitary

BIOCHEMISTRY (25 decks)

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