Brainscape's Knowledge GenomeTM

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


See full index

Neuro Block 4 - KJ > Homeostasis > Flashcards

Homeostasis Flashcards

1
Q

What is the key integrator of homeostatic systems?

A

Hypothalamus

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

What are homeostatic systems not limited to?

A

Autonomic nervous system

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

What is the largest threat to thermoregulation and why?

A

Overheating

-We have no mechanism for cooling out body but we do have mechanisms to heat it up

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

How do we resist hypothermia?

A

Heat conservation & increased heat production (shivering)

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

What is the body’s set point?

A

37C (if it drops below or above we feel cold and hot)

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

How do we vasodilate (to avoid too high of temperature)?

A
  1. Local temperature sensors cause release of NO
  2. NO stimulates Guanylyl Cyclase (enzyme) which converts GTP to cGMP
  3. Then cGMP causes MLCK to relax =vasodilate
    {cGMP–> activates protein kinase G which phosphorylates proteins and decreases intracellular calcium –> relaxing muscles}
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do core temperature sensors do when you’re hot?

A

Send signals to the CNS to activate sympathetic nerve outflow (both adrenergic & cholinergic). This increases skin blood flow and increases sweating.

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

What are two mechanisms the body uses to avoid too low of temperature?

A
  1. Cold stimulates skin receptors to release NE which constricts blood vessels.
  2. Core temp sensors stimulate CNS to increase sympathetic nervous system outflow –> causes decreased skin blood flow.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

IMPORTANT: What causes a fever???

A
  1. Pyrogen (IL-1, IL-6, TNF-alpha) stimulates hypothalamus

2. Hypothalamus produces PGE2 in medial pre-optic area causing shivering and increased metabolic rate

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

What is important to remember about fevers?

A
  1. PGE2 change the set point

2. Hypothalamic temperature does NOT change, it receives input from sensors elsewhere

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

What causes hot flashes in nearly 80% of post-menopausal women?

A

An extremely narrow (unmeasurable) thermoregulatory zone

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

What is blood pressure determined by?

A 
BP = (Cardiac output/Flow) X (Peripheral resistance)
BP = (Heart rate) X (Stroke volume) X (Total peripheral resistance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do sympathetic nerves do in regulation of blood pressure?

A
  1. Interact with beta1 receptors to stimulate heart rate
  2. Interact with beta1 receptors to increase stoke volume
  3. Interact with alpha1 receptors to increase resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of system is the vagus nerve associated with in bp regulation? What does vagus nerve do to bp?

A
  1. Parasympathetic nerve

2. Releases ACh to interact with muscarinic receptors in the heart to slow heart rate

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

How to baroreceptors regulate blood pressure? (simple version)

A
  1. If bp is low, sensory fibers are less stimulated
  2. Sensory fibers stimulate inhibitiroy interneurons less
  3. Inhibitory interneurons do NOT inhibit rest of pathway
  4. Rest of pathway is stimulated which causes constriction of the muscle (stimulation of sympathetic nerve ending)
  5. Constriction of the muscle causes an increase in bp (vasoconstriction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where are stretch receptors located?

A

Carotid arteries & Aortic arch

17
Q

Pathway from stretch receptors to Nucleus Tractus Solitarius (NTS)?

A
  1. Stretch receptors sense stretch (blood pressure) [High bp]
  2. As blood pressure increases, firing rate increases
  3. Impulses are carried by glossopharyngeal and vagus nerve to medulla
  4. Nerves terminate in NTS of medulla.
18
Q

What is the pathway from the NTS to the change in bp?

A
  1. Neurons in the NTS suppress neurons in rostal ventrolateral medulla (sympathoexcitatory area)
  2. These neurons excite sympathetic preganglionic neurons in the interomediolateral column of the thoracic cord.
  3. Sympathetics usually increase heart rate (beta1), stroke volume (beta1) and resistance (alpha1) to raise bp.
  4. Since input from baroreceptors inhibits activation of sympathetic nerves (and release of NE to elevate heart rate, stroke volume, resistance) the net effect is lessened intensity of the increase in bp (decrease in bp)
19
Q

What might causes orthostatic hypotension in people my age?

A

Dehydration (less blood volume = lower bp

20
Q

What happens if the bp in the carotid and aorta drops?

A
  1. Less activation of glossopharyngeal & vagus nerve
  2. Less stimulation of NTS
  3. Less inhibition of rostral ventrolateral medulla
  4. Greater stimulation of preganglionic sympathetics in thoracic cord
  5. Increases heart rate, stroke volume and resistance
  6. Lessens drop in blood pressure
21
Q

What is the pump that generates pressure differentials when we breathe?

A

Diaphragm and External Intercostals

22
Q

What is our breathing pacemaker that initiates breathing?

A

Pre-Boetzinger area of ventrolateral medulla

23
Q

How does the pacemaker (Pre-Boetzinger area) work?

A

Stimulates C3-C5 via the phrenic nerve to innervate the diaphragm

24
Q

What type of nerve is the phrenic nerve that innervates the diaphragm?

A

Somatic, releases ACh onto nicotinic receptors on the diaphragm. (all somatic nerves coming off spinal cord release ACh onto nicotinic)

25
Q

How do you get Hydrogen ion from Carbon dioxide?

A

Carbonic anhydrase (CA)

26
Q

What is the main input into the Pre-Boetzinger area?

A

Parafacial respiratory center

27
Q

What does the parafacial respiratory center sense?

A
  • CO2 (actually H+) and excites Pre-Boetzinger area

- It also directly excites muscles involved in active expiration (abdominals)

28
Q

What happens if you have a lack of carbon dioxide sensors?

A

(CO2 sensors are in parafacial respiratory center)

  • Hyperventilation while sleeping (Fatal if untreated)
  • People with this condition need to connect a device while they’re sleeping
29
Q

What nerve does the pacemaker control? What happens when you activate this nerve?

A
  • Phrenic nerve

- Cause diaphragm to contract

30
Q

What is the voluntary mechanism that controls urination?

A

External sphincter consists of skeletal muscle & is VOLUNTARY
-ACh stimulating nicotinic receptors (like all skeletal muscles)

31
Q

What is the involuntary mechanism that controls urination?

A

Internal sphincter and detrusor (wall) are innervated by the parasympathetic nervous system (involuntary)
-ACh stimulating muscarinic receptors

32
Q

How do you think bladder filling is sensed?

A

Stretch receptor - barorecptor!

33
Q

What happens when the bladder fills?

A

It sends afferent signals to the medial prefrontal cortex, which normally suppresses voiding.

34
Q

How will you treat incontinence (drugs)?

A

Anti-muscarinic drugs/muscarinic receptor antagonists

35
Q

What is the role of the pontine micturition center?

A

-Activates sacral cord to stimulate preganglionic parasympathetic nerves (involuntary control)
[-Also activates inhibitory interneurons influencing motoneurons innervating the external urethral sphincter]
-NET: relaxation of external (voluntary) sphincter and contraction of the urinary bladder via parasympathetic nerves

36
Q

What neurotransmitter does the parasympathetic nervous system use primarily?

A

Acetylcholine!

37
Q

What is dis-inhibited during urination?

A

Micturition center

38
Q

How is urination controlled?

A

Activation of pudendal nerve to relax external sphincter.

[Involuntarily - mediated by activation of parasympathetic nerves]

Neuro Block 4 - KJ (12 decks)

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