Body Systems L13 Flashcards by Jade Benita McLaughlin

What is contractility?

 Contractile ability -> cardiac muscle at a given period.

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Describe the effect of incr. ventricular contraction on stroke volume

 Incr. ventricular contraction -> incr. stroke volume

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What is an inotropic effect?

 Effects which alter the contractility of the heart.

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What are positive inotropic effects? Give an example.

 Positive inotropic effects:
Effects which incr. contractility -> heart
Eg. Sensory Nervous System & adrenaline
->SNS also incr. conduction velocity & cardiac impulse.

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What are negative inotropic effects? Give an example & incl. how this is carried out.

 Negative inotropic effects:
Effects which decr. contractility -> heart
Eg. Peripheral Nervous System (ACh)
->Mainly exerted on atria
&raquo_space;Vagal nerve doesn’t innervate ventricles.

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Describe contractility & filling times of the heart when Heart rate is 70bpm

HR -> 70bpm
 Total Filling time: 0.8s
Diastole: 0.53s
Systole: 0.27s

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Describe contractility & filling times of the heart when Heart rate is 150bpm and no sensory nervous system tone is present. Explain the consequences of these statistics.

HR -> 150bpm -> No SNS tone
 Total filling time: 0.4s
Diastole: 0.13s
Systole: 0.27s
–> Not enough time to refill ventricles for effect.
–> Without sympathetic nervous system intervention -> contraction of ventricles too severe & rapid for sufficient refill of ventricles for transport of adequate blood supply to tissues.

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Describe contractility & filling times of the heart when Heart rate is 150bpm and sensory nervous system tone is present. Explain the consequences of such statistics.

HR -> 150bpm -> SNS tone
 Total filling time: 0.4s
Diastole: 0.22s
Systole: 0.18s
```
    --> Enables sufficient filling time by extension of diastolic phase ***
```

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What is the afterload?

 Pressure opposing ejection of blood from heart

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What factor is the afterload affected by?

Influenced -> Blood vessel tone -> Vasoconstriction/dilation

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What does the afterload have an affect on?

Major effect -> cardiac output.

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What is the equation for blood pressure?

Include the units/eqns. for facors in the eqn.

• Blood Pressure = Cardiac Output x Total Peripheral Resistance
 Cardiac Output -> ▲HR & SV
 Total Peripheral Resistance -> ▲Arteriolar Radius

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Describe how the blood vessel tone is controlled

•	Blood vessel tone controlled -> interrelated processes
	Automatic / intrinsic 
	Short term 
	Long term 
Control measures.

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What affect does decr. oxygen and incr. co2 have on pulmonary circulation?

• Pulmonary Circulation:

- Decr. O2 & Incr. CO2 -> constriction -> arterioles.

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Describe factors which may result in altered blood pressure / volume

Physical stress
Eg. Trauma, high temp, etc.
Chemical changes
Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites
Increased tissue activity / Intrinsic Control

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Describe homeostasis/ regulation & response of blood pressure

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• Response & Regulation of Blood Pressure:
Homeostasis:
- Altered Blood pressure / volume
Physical stress
Eg. Trauma, high temp, etc.
Chemical changes
Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites
Increases tissue activity / Intrinsic Control
- Inadequate blood pressure & flow
»Autoregulation:
 Decr. resistance & incr. blood flow
> Homeostasis returned.
- Insufficient Autoregulation:
Stimulates receptors -> sensitive to systemic changes -> blood pressure /
Chemistry.
Activates cardiovascular centres -> Central Nervous System
Elevates Blood pressure -> Short Term
&raquo_space;Stimulation -> heart rate & peripheral vasoconstriction
–» Sensory Nervous System.
Return -> Homeostasis.

Describe the process of autoregulation of blood pressure & how it may have been caused.

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Describe what occurs if autoregulation of blood pressure is insufficient

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Insufficient Autoregulation:
Stimulates receptors -> sensitive to systemic changes -> blood pressure /
Chemistry.
Activates cardiovascular centres -> Central Nervous System
Elevates Blood pressure -> Short Term
»Stimulation -> heart rate & peripheral vasoconstriction
–» Sensory Nervous System.
Return -> Homeostasis.

Give examples of vasodilatory metabolites

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• Vasodilatory metabolites

 H+ / CO2 / K+ / Adenosine / Lactate

Describe the state of the vessel & causative factors of this for active tissues.

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• Active tissues:
Vessel vasodilated
&raquo_space;Response -> metabolites
>Incr. Blood flow -> tissue.

Describe the state of the vessel & causative factors of this for inactive tissues.

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• Inactive tissues:
Vessel vasoconstricted
&raquo_space;Absence -> excess metabolites

State where the chemoreceptors can be located.

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• Chemoreceptors:
Medulla oblongata:
» Cardioregulatory centre
Carotid Body

State where the baroreceptors can be located.

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• Baroreceptors:
Wall -> internal carotid artery
Aorta

Describe actions of the baroreceptors during times of inadequate blood supply / blood pressure

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•	Inadequate Blood supply / Decr. Blood Pressure:
-	Inhibition -> baroreceptors
	 Activation 
 Cardioacceloratory Centre
Vasomotor Centres
	Inhibition
 Cardioinhibitory Centre
       >> Incr. Cardiac Output &amp; Heart Rate
-	Vasoconstriction

Describe actions of the baroreceptors during times of increased blood pressure

``` • Rise -> Blood Pressure: - Stimulation -> Baroreceptors  Activation Cardioinhibitory Centre  Inhibition Cardioacceloratory Centre Vasomotor Centres >> Decr. Cardiac Output & Heart Rate - Vasodilation. ```

Describe the actions of the chemoreceptors found in the medulla oblongata when detection of incr, Co2 & decr. pH

• Chemoreceptors -> Medulla Oblongata: - Detect incr. CO2 decr. pH - Vasodilation -> Cerebral Vessels >> Incr. Blood flow -> Brain.

Describe the actions of the chemoreceptors found in the carotid body when detection of incr, Co2 & decr. pH

``` • Chemoreceptors -> Carotid Body: - Detect incr. CO2 / decr. pH  Stimulate cardioaccelatory centre  Inhibit cardioinhibitory centres  Stimulate vasomotor centres >> Incr. Cardiac Output, Vasoconstriction & Heart Rate ```

Describe the actions of the chemoreceptors when detection of incr. Co2 & decr. pH

• Chemoreceptors -> Medulla Oblongata: - Detect incr. CO2 / decr. pH - Vasodilation -> Cerebral Vessels >> Incr. Blood flow -> Brain. ``` • Chemoreceptors -> Carotid Body: - Detect incr. CO2 / decr. pH  Stimulate cardioaccelatory centre  Inhibit cardioinhibitory centres  Stimulate vasomotor centres >> Incr. CO & incr. Heart Rate ```

Describe the actions of the chemoreceptors when decr. oxygen detected.

- Detect decr. O2 | - Incr. respiratory rate

Describe intrinsic/autoregulation of blood flow & both methods of recovery if autoregulation insufficient

• Intrinsic / Autoregulation -> Blood Flow: - Homeostasis Disturbed Physical Stress Eg. Trauma , High Temp Chemical Changes Eg. Decr. O2 / decr. pH / Incr. CO2 / Incr. vasodilatory metabolites Incr, tissue activity - Inadequate blood pressure & blood flow - Autoregulation: Decr. resistance Incr. blood flow - If autoregulation insufficient: 1. - Stimulation -> receptors Sensitive -> changes -> systemic blood pressure / chemistry - Activation -> Cardiovascular centres -> Central Nervous System - Short-term incr. -> Blood pressure Sensory nervous system stimulates Heart rate & peripheral vasoconstriction If response to control of blood flow still insufficient following stimulation -> cardiovascular centre sensory receptors 2. - Endocrine response stimulated - Long-term incr. -> Blood pressure Angiotensin II -> Vasoconstriction Aldosterone, ADH etc. -> Blood Volume >>Return -> homeostasis.

Describe both methods of recovery of blood flow if intrinsic / autoregulation insufficient

- If autoregulation insufficient: 1. - Stimulation -> receptors Sensitive -> changes -> systemic blood pressure / chemistry - Activation -> Cardiovascular centres -> Central Nervous System - Short-term incr. -> Blood pressure Sensory nervous system stimulates Heart rate & peripheral vasoconstriction If response to control of blood flow still insufficient following stimulation -> cardiovascular centre sensory receptors 2. - Endocrine response stimulated - Long-term incr. -> Blood pressure Angiotensin II -> Vasoconstriction Aldosterone, ADH etc. -> Blood Volume >>Return -> homeostasis.

Describe recovery of blood flow using the cardiovascular centres of central nervous system if autoregulation insufficient

- Stimulation -> receptors Sensitive -> changes -> systemic blood pressure / chemistry - Activation -> Cardiovascular centres -> Central Nervous System - Short-term incr. -> Blood pressure Sensory nervous system stimulates Heart rate & peripheral vasoconstriction

Describe recovery of blood flow using the endocrine system if autoregulation & stimulation of cardiovascular centre insufficient

If response to control of blood flow still insufficient following stimulation -> cardiovascular centre sensory receptors - Endocrine response stimulated - Long-term incr. -> Blood pressure Angiotensin II -> Vasoconstriction Aldosterone, ADH etc. -> Blood Volume >>Return -> homeostasis.

What is a requirement of inotropic influences?

• Inotropic influences must be integrated with chronotropic influences.

What is blood pressure?

 Force placed on walls of blood vessels by blood as it flows.

Briefly describe how change of blood flow is controlled

 Changes -> blood flow -> controlled by changes in diameter -> arteries & cardiac output.

What is the capillary hydrostatic pressure?

• Capillary hydrostatic pressure: |  Minimum pressure required -> capillary exchange -> exchange of fluids & substances across capillary networks.

Body Systems L13 Flashcards

(37 cards)