Brainscape's Knowledge GenomeTM

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


See full index

BIO202 > Chapter 9 (Maintaining Internal Balance) > Flashcards

Chapter 9 (Maintaining Internal Balance) Flashcards

1
Q

direct vs. indirect cell signalling

A
  • direct: cells communicate via aqueous pores that connect adjacent cells (through gap junctions)
  • indirect: signalling cell releases a chemical messenger into the extracellular environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

differentiate between the types of indirect cell signalling: paracrine, autocrine, endocrine

A
  • paracrine: chemical messengers diffuse to nearby cells
  • autocrine: chemical messenger binds to receptors on the same signalling cell
  • endocrine: hormones travel via circulatory system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

exocrine vs. endocrine glands

A
  • exocrine: secretions via ducts onto body surface (or gut surface)
  • endocrine: secrete hormones carried by circulatory system (long distance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

hormones

A
  • circulate through blood
  • activate receptors on target tissue cells
  • act as first messengers in a series of messengers that lead to a specific response
  • released into the blood in small quantities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

direct feedback loop

A

stimulus is detected and integrated by the same endocrine organ to secrete hormone

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

first-order feedback loop

A
  • one step (one neuron) between integration centre and target organ
  • stimulus detected by sense organ that sends signal via sensory neuron to integrating centre, signal sent via neuron to target organ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

second-order feedback loop

A
  • two steps from integrating centre to target organ

- integrating centre to endocrine gland via neuron; endocrine gland to target organ via circulatory system (hormone)

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

third order feedback loop

A
  • three steps from integrating centre to target organ
  • integrating centre to endocrine gland 1 via neuron
  • endocrine gland 1 to endocrine gland 2 via circulatory system and hormone 1
  • endocrine gland 2 to target organ via circulatory system and hormone 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the synthesis of peptide hormones.

A
  • ribosomes on RER synthesize large preprohormone
  • preprohormone enters RER, signal sequence gets cleaved off and resulting prohormone is packaged into vesicle
  • vesicle move to Golgi apparatus for processing and sorting
  • prohormones from Golgi get packaged into secretory vesicles
  • inside these secretory vesicles the prohormone is cleaved into the active hormone
  • secretory vesicle fuses with plasma membrane, exocytosis releases hormone into extracellular environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Amino acids typically act as ___.

A

neurotransmitters

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

cytokines

A

paracrine peptides that are synthesized only on demand

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

How do peptide messengers act on their target cells?

A
  • dissolve in extracellular fluid and bind to transmembrane receptors
  • they are hydrophilic so cannot pass through membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Steroid hormones are derived from ___.

A

cholesterol (lipids)

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

What are the major classes of steroid hormones?

A
  • mineralocorticoids
  • glucocorticoids
  • reproductive hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

mineralocorticoids

A
  • regulate kidney sodium uptake
  • fluid and electrolyte balance
  • example: aldosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

glucocorticoids

A
  • aka stress hormones
  • metabolism
  • glucose production
  • breakdown of proteins
  • release of fatty acids
  • regulate immune system and inflammatory response
  • example: cortisol
17
Q

Are steroids hydrophilic or hydrophobic? How does that affect its synthesis?

A
  • steroids are hydrophobic
  • since they can pass through membranes, they cannot be stored
  • must be synthesized on demand
18
Q

Explain the equilibrium formed between messengers (e.g. steroids) and carrier proteins (e.g. albumin)

A
  • high concentration of messenger near signalling cell diffuses into blood
  • equilibrium is established between free messenger and messenger bound to carrier protein
  • as free messenger diffuses into target cell, concentration decreases and more messengers dissociate from carriers (and vice versa)
19
Q

What are biogenic amines derived from? What are some examples? Hydrophobic/hydrophilic?

A
  • amino acid derivatives
  • examples: catecholamines (epinephrine, norepinephrine, dopamine), serotonin, histamine, acetylcholine, thyroid hormones
  • most hydrophilic but thyroid hormone is hydrophobic
20
Q

agonist vs. antagonist

A
  • agonist: chemical binds to and activates receptor

- antagonist: binds to but does not activate receptor; prevents binding of natural ligand and prevents response

21
Q

law of mass action

A
  • binding of receptor to ligand will produce complex; active complex produces response
  • reversible binding
  • balance between concentration of ligand and proportion of receptors bound (as one increases the other increases)
22
Q

What does affinity refer to? What does high vs. low affinity mean?

A
  • affinity is the ability of a receptor to recognize and bind to ligand and induce response
  • high affinity = more binding with lower concentration of ligand (lower Kd)
  • low affinity = higher Kd
  • Kd is concentration of ligand at which 50% receptors bound
23
Q

down-regulation vs. up-regulation

A
  • down-regulation: less receptors produced (due to action of agonist) (e.g. when more heroin is consumed, less endorphin receptors are produced)
  • up-regulation: more receptors produced (due to action of antagonist) (e.g. when more caffeine is consumed, more adenosine receptors are produced)
24
Q

Describe signal transduction by intracellular receptors.

A
  • hydrophobic ligand passes through cell membrane and binds to ligand-binding domain on intracellular receptor
  • intracellular receptor undergoes conformational change
  • receptor-ligand complex translocates to nucleus
  • DNA binding domain of receptor binds to DNA and interacts with other transcription factors
  • rate of transcription of target genes is altered
25
Q

Do intracellular receptors produce short term or long term effects and why?

A
  • effect is long term because receptor-ligand complex binds to regulatory elements in DNA
26
Q

Describe signal transduction by receptor-enzymes using the example of guanylate cyclase.

A
  • ligand binds to guanylate cycle, changing its conformation and activating it
  • activated receptor catalyzes conversion of GTP to cGMP
  • cGMP acts as second messenger, binding to PKG
  • PKG is activated and phosphorylates proteins on serine/threonine residues
27
Q

What are the 3 domains that make up receptor-enzymes

A
  • extracellular ligand-binding domain
  • transmembrane domain
  • intracellular catalytic domain
28
Q

Describe signal transduction via G-protein coupled receptors.

A
  • ligand binds to GPCR, causing conformational change
  • activates G protein; alpha subunit releases GDP and binds GTP
  • some subunit(s) translocate through membrane to interact with amplifier enzyme, which activates a second messenger
  • activated second messenger can activate or inhibit cellular pathways

BIO202 (7 decks)

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