lab this week endocrinology of hormone supplementation write a paragraph in which you 1) identify...
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Lab this Week
Endocrinology of Hormone Supplementation
Write a paragraph in which you 1) identify the major objectives of the paper (the most important questions it addresses), and 2) a concise summary of their most important findings. Bring this text with you to lab, ready to turn in to the lab instructor.
Classes this Week
• Glucose Homeostasis:Ch 16A p.555-567 and Ch 16B.1 p. 569-580
• Endocrinology Chapter 11 A-D, F
1QQ # 3 for 10:30Name on top edge, back side of paperAnswer on blank side of paper.
1. Describe what would happen if a person were injected with a drug that acts like Interleukin-6?
2. How can a feedforward response be distinguished from a negative feedback response?
3. What is the difference between heat stroke and heat exhaustion, and how can they be distinguished by physical examination?
4. How do Tylenol and other NSAIDs minimize a fever?
1QQ # 3 for 11:30Name on top edge, back side of paperAnswer on blank side of paper.
1. Describe what would happen if a person were injected with a drug that acts like Interleukin-6?
2. How can a feedforward response be distinguished from a negative feedback response?
3. What is the difference between heat stroke and heat exhaustion, and how can they be distinguished by physical examination?
4. How do Tylenol and other NSAIDs minimize a fever?
Positive feedback
• Examples of Positive Feedback in Physiology– Heat stroke (diagrammed earlier)– formation of blood clot– menstrual cycling of female sex hormone concentrations– generation of action potentials in nerve fibers– uterine contractions during childbirth
• Each of these examples terminate naturally (self limiting)
• Inherently unstable but some are essential for life!
Glucose Homeostasis
Another detailed example of negative feedback
Graph your daily caloric intake over a 48 hour period
6am 6am6pm 6pmNoon NoonMN MN
Cal
orie
sco
nsum
ed
6am Noon
PlasmaGlucose
?
?
Overlay absorptive and post-absorptive phases on the graph
Phases:absorptive, post-absorptive, and fasting
Homeostasis of Plasma Glucose Concentration
• 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)?
MuscleAdiposeLiverNervousOther
Fig. 16.01A
bsor
ptiv
e P
hase
Lipoprotein Lipase
Once inside, glucose is converted to something else, thereby maintaining a concentration gradientfor facilitated diffusion ofglucose into cells.
=“sinks”Entry requiresGlut-4 transporters
Activates some enzymes, inactivates others
GLUT-4
Peptide hormone
Exercise (via an undescribed mechanism) increases the number of glucose transporters in muscle cell membrane
Diabetes mellitus:T1DM =beta cells fail to produce adequate insulin (5%)T2DM = target cells “resistant” (less responsive) to insulin
↑ plasma glucose →↑insulin secretion→↑glucose uptake into cells →↓ plasma glucose
Fig. 16.07Identify sensors, afferent pathway,integrator,efferent pathway,effectors
How is insulin secretion affected if plasma glucose is lower than set point?
Which cell types have insulin receptors?
Islets of Langerhans
Alpha cells secrete glucagonBeta cells secrete insulinDelta cells secrete somatostatin
Route of blood
LiverTypical vasculature: Artery-Arteriole-Capillary-Venule-Vein-Heart
?
The Integrator integrates multiple inputs
Glucose uptake, Storage, Lipogenesis
WHY? FF
Thinking about food, aroma,Factors that influence Insulin Secretion
and other Incretins