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For 1QQs. Last name, First name. Question # a b c d e. Announcements. Turn in Personal Information (place on Piano.) Reading and Chapter Questions Will finish Thermoregulation Today and Glucose Homeostasis on Monday By Monday,complete all Glucose Homeostasis Questions.

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For 1qqs

For 1QQs

Last name, First name

Question #

a b c d e


Announcements

Announcements

  • Turn in Personal Information (place on Piano.)

  • Reading and Chapter Questions

    • Will finish Thermoregulation Today and

    • Glucose Homeostasis on Monday

    • By Monday,complete all Glucose Homeostasis Questions


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1QQ Sample Questions

Name on top edge, back side of paper

Answer on blank side of paper.

Answer one of the following:

  • The San people of Botswana were clothing made of tanned animal skins. A) What would be the preferred type of clothing for their hot desert environment, b) why would it be preferred (think heat exchange mechanisms) and c) why do you suppose they don’t wear what would be preferred?

  • What is the difference between a reflex and a negative feedback loop?


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1QQ # 2 for 8:30

Name on top edge, back side of paper

Answer on blank side of paper.

  • For the negative feedback loop for thermoregulation

    • The hypothalmus is an afferent pathway

    • Somatic nerves are the efferent pathway to sweat glands

    • Skeletal muscle tone would be increased as a response to a drop in core body temperature

    • Peripheral nerves are the afferent pathway that convey skin temperature information

    • Cutaneous arterioles would dilate in response to a drop in core body temperature.


For 1qqs

1QQ # 2 for 9:30

Name on top edge, back side of paper

Answer on blank side of paper.

  • For the negative feedback loop for thermoregulation

    • The hypothalmus is an efferent pathway

    • Somatic nerves are the efferent pathway to skeletal muscles

    • Skeletal muscle tone would be decreased as a response to a drop in core body temperature

    • Peripheral nerves are the afferent pathway that convey skin temperature information

    • Sympathetic nerves would lead to constriction of cutaneous arterioles in response to a drop in core body temperature.


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Convective heat loss

Conductive heat loss

Skin temp

Radiative heat loss

Detected by thermoreceptors in skin

Hypothalamus

Heat loss

Sympathetic nerves

Sweat Glands

Muscle tone

Heat production

Relax smooth muscle in cutaneous arterioles

Activity in sensory nerves

Blood flow to skin

Sweat production

Evaporative heat loss

And Core body temp

Heat loss by conduction & radiation

Core temp.

Add coversor clothingor enter sleeping bag

Central thermoreceptors

Cerebral cortex

Somatic nerves

Voluntary behaviors

Remove coversTurn on fan, etc via

Somatic nerves

Skeletal Muscles


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~37oC

Be able to explain the physiology in each of these situationswith a detailed diagram of negative feedback responses and

the modes of heat exchange involved.


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Which roofers are most appropriately dressed for the job?

No shirts

Red shirts

  • 1st day on the job

    • Increase body temp….. Delayed sweating via negative feedback

  • 10th day on the job

    • Sweating precedes changes in core body temperature

    • and sweating is increased

    • And salt loss in sweat is minimized

Responses begin even before core temperature increases! Not just negative feedback, this is Feedforward (requires experience). FF is evidence of Acclimitization.

Advantage of feedforward: anticipates disruption and minimizes fluctuation from the set point.


Acclimatization feedforward

Acclimatization & Feedforward

  • Deviations from set point are minimized

  • Learned (by experience)

  • Anticipates changes of a physiological parameter

  • Response begins before there is a change in the physiological variable

  • Minimizes fluctuations


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Blood Pressure

Blood Flow to brain

Cutaneous vasodilation

Disrupted functionof neurons

Sympathetic outflow

Sweating

Heat Stroke

Massive Cutaneous Vasodilation

Excessive Sweating

Blood volume

Treating Heat Stroke


Positive feedback

Positive feedback

  • Inherently unstable

  • Examples of Positive Feedback in Physiology

    • Heat stroke

    • formation of blood clot

    • menstrual cycling of female sex hormone concentrations at ovulation

    • generation of action potentials in nerve fibers

    • uterine contractions during childbirth

  • Each of these examples terminate naturally (self limiting)

Homeostasis is achieved by negative feedback loops: the integrator detects deviations from set point and orchestrates responses produced by effectors that return the parameter toward the set point.


P 579 fig 16 18

Central &PeripheralThermoreceptors

p. 579 Fig 16-18

If setpoint is suddenly reset to a higher temperature, then actual temperature is LESS THAN the new set point, so one feels “cold” and adds clothing, curls up, and shivers. These are “Chills.”

  • Explain “chills” at onset of a fever

  • Explain “sweat” when a fever “breaks”

  • How does Tylenol reduce a fever?

Tylenol and other non-steroidal anti-inflammatory drugs (NSAIDS) suppress the production of eicosanoids (IL-1, IL-6, etc) so effect of these on the set point in hypothalamus is minimized.

If setpoint is reset to a lower temperature or back to normal, then actual temperature is GREATER THAN the new lower set point, so one feels “hot” and removes clothing, fans, and sweats. These are “the sweats” when a fever breaks.

To reach new,

Higher set point


Plasma glucose homeostasis

Plasma Glucose Homeostasis

  • Glucose metabolism

  • Hormonal Control

  • Disruptions of glucose homeostasis

  • A Case Study


Homeostasis of plasma glucose concentration

Homeostasis of Plasma Glucose Concentration

  • Normal physiological range: 65-100 mg/dl

  • What is the set point?

  • Why is too much plasma glucose harmful?

  • Plasma glucose concentration = glucose entering the plasma – glucose leaving the plasma

  • What are the mechanisms that regulate plasma glucose concentration?

  • What are the components of the negative feedback loop:

    • Glucose receptors?

    • Afferent pathway?

    • Integrator?

    • Efferent pathway(s)?

    • Effector organ(s)?

Phases:absorptive, post-absorptive, and fasting


Graph your daily caloric intake over a 48 hour period

Graph your daily caloric intake over a 48 hour period

PlasmaGlucose

?

?

Calories

consumed

6am

Noon

6am

6am

Noon

MN

Noon

MN

6pm

6pm

Overlay absorptive and post-absorptive phases on the graph


Fig 16 01

=sink

Fig. 16.01

Lipoprotein Lipase

Absorptive Phase

Hepatic Portal System

Once inside, glucose is converted to something else, thereby maintaining a concentration gradientfor facilitated diffusion ofglucose into cells.


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