Your Future in Physiology

Class meetings

• Two 1QQs on Monday– One on Andro Lab

• Grants to Publications

• The King et al paper

– One as usual on lecture material

• Readings and chapter questions for Endocrinology Chpt 11.

Lab

• Frog behavior & reflex lab– Intact– Single pithed– Double pithed

10:30 Class…. Return 1QQ#3 to me to re-enter grades.

Check the Moodle Site regularly.

1QQ#5 for 10:30Write the letter of each correct response.

1. During the post-absorptive phasea) glycogenesis occurs in hepatocytesb) gluconeogenesis occurs in adipocytesc) most cell types metabolize fatty acids and ketonesd) hepatocytes convert amino acids to glucosee) glucagon levels are elevated and insulin levels are low.

1QQ#5 for 11:30Write the letter of each correct response.

1. During the post-absorptive phasea) gluconeogenesis occurs in hepatocytesb) lipolysis occurs in adipocytesc) most cell types metabolize fatty acids and ketonesd) hepatocytes convert fatty acids to ketonese) glucagon levels are low and insulin levels are high.

Follow-up to Reactive Hypoglycemia

• Explain the origin of hypoglycemia

• Explain the headache, tachycardia, cold, clammy skin, and disorientation.

• Why replace Cheerios with a burger?

Link to Sugar Stacks webpage with Sugar content of Coke

New York Bans Big Gulp Sugary Drinks

39 gin 12 oz.

65 g in 20 oz. 108 gin 1 liter = 34 oz.

Board Diagram ofReactive Hypoglycemia

Stress,Emergency (fight or flight)

Effect onBeta cells

Effect on Alpha Cells

Real World Physiology

Does the timing and composition of a meal matter for athletes before an event?

How doesa cell “know” which fuels to metabolize?

Endocrine Organs (Table 11-1)

• Pituitary Gland• Thyroid Gland• Pancreas• Gonads• Gastrointestinal Tract• Heart• Kidney• Hypothalamus• Liver• Etc.

Hormone: chemical messengerscarried by blood to target cells

upon which they act.

Only those cells having receptorsCan respond to a given hormone

Hormone

Paracrine agent

Autocrine agent

Neurotransmitter

Neuromodulator

What we need to know about hormones

• How and where are they synthesized?• How is a hormone stored and released?• How is a hormone transported in the blood?• What is the fate of a hormone once released from

a gland?• How does a hormone interact with its target cells?• What responses are produced by a hormone in its

target cells?• How long do the effects last?

All the answers are all related to the chemical structure of a hormone.

3 Chemical Classes of Hormones

• 1: Amine hormones (from amino acid tyrosine)– Thyroid hormones – Adrenal medullary hormones (catecholamines)

• 2: Peptide hormones (peptides & proteins)• 3: Steroid Hormones (derivatives of cholesterol)

Fig. 11.01

Catecholaminessoluble in plasma

ThyroidHormones Not soluble in plasma, bound & free

AmineHormones

Adrenalmedulla

NT

NT

Fig. 11.02Peptide Hormones

Examples of Peptide Hormones:Insulin, glucagonprolactin, erythropoietin,parathyroid hormone,gastrin, leptin, growth hormone,oxytocin, vasopressin,FSH, LH, GHRH, andmany more!

Cell surface receptors on target cells

Guess peptide!

Soluble in plasma

e.g.Beta cell

Fig. 11.03Steroid hormones

not soluble in plasma, not storable in vesicles

Target cells have intracellular receptors.Changes is gene expression.

Timecourse: longer latency, longer lasting

Bound & Free