Ex Phys Hormones

Main functions of Epinephrine

1. Glycogenolysis in liver and muscle

2. Lipolysis in adipocytes and muscle

3. Blocks glucose entry into muscle cells

4. Gluconeogenesis in liver

Main functions of GH

1. Lipolysis in adipocytes

2. Blocks glucose entry

3. Gluconeogenesis

Main functions of Glucagon

1. Glycogenolysis in liver and muscle

2. Lipolysis in adipocytes

3. Gluconeogenesis in liver

Main functions of Insulin

1. Facilitates the uptake and storage of glucose by GLUT4 translocation (increases with SNS=BG spared)

Main functions of cortisol

1. Lipolysis in adipocytes

2. Blocks glucose entry

3. Gluconeogenesis in liver

Common pathway in hormones

Reception- Transduction- Induction

Reception

Hormone binds to receptor

Transduction

Signal s transferred or converted into intracellular activity

Induction

Cellular response occurs

Provide examples of reception, transduction and induction for any hormone and cellular effect noted in class

EPI binds to a beta receptor and activates a G protein (i.e., reception), activates adenylate cyclase (AC) to facilitate the breakdown of ATP to cyclic AMP (i.e., transduction) that will induce lipolysis (i.e., induction).

5 main adrenergic receptors

beta-1, beta-2, beta-3, alpha-1, alpha-2

When hormones bind to B1

Increase heart rate, glycogenolysis, lipolysis

When hormones bind to B2

Bronchodilation, vasodilation

When hormones bind with B3 receptors

Lipolysis

When hormones bind with A1 receptors

Phosphodiesterase, vasoconstriction

When hormones bind to A2 receptor

Opposite of B1 and B2, decrease in insulin secretion

Pathway for all receptors (besides A1)

Epinephrine binds- G Protein stimulated-Adenylate cyclase enzyme is activated- increases cAMP- responses on tissues

Bioavailability

Amount of a hormone that is available to enter target cells and produce a biological effect

Half life of EPI

2-3 Mins

Half life of insulin, GH, glucagon

15-20 mins

Half life of steroids

2-6 hours

Henneman’s size principle:

• Type I: Small motor neurons, low recruitment threshold, recruited first.

• Type IIa: Intermediate recruitment threshold, recruited next.

• Type IIx: Larger motor neurons, high recruitment threshold, recruited last.

Myonuclear domain theory

Increased muscle size → Increased demand for protein synthesis → Additional myonuclei may be needed to support continued growth.

Satellite cells →

Activation → Proliferation → Differentiation → Fusion → Additional myonuclei → Support for hypertrophy.

What if there is an increase in H+?

It can bind to troponin instead of CA2+, which decreases calcium recycling, decreases pH, and denatures enzymes

3 Biochemical properties of skeletal muscle

1. Oxidative capacity

2. Myosin ATPase isoform

3. Abundance of contractile proteins

Oxidative capacity

1. Number of oxidative enzymes

2. Capillary density

3. Mito density

4 Main contractile properties

1. Max force production (MQ, ST)

2. Speed of contraction

3. Maximal power output

4. Muscle fiber efficiency

How is force regulated in a muscle

1. Type of MU recruited

2. Initial muscle length

3. Nature of neural stimulation

Flow equation

Change in pressure1-change in pressure2 / resistance

Resistance equation

Length x viscosity / radius^4

When it is less viscus, there is ____ resistance

Less

Small radius= ___ resistance and ___ flow

Increase, decrease

Main purpose of heart

To make a pressure differential between left ventricle and aorta

Purpose of the CR system

1. Transport O2 and nutrients to tissue

2. Removal of CO2 from tissue

3. Regulation of body temp

2 Major adjustments of BF

1. SV+CO+EF

2. Redistribution of BF from viscera to active musculature

How is BF redistibuted?

Autoregulation via BCSs which eventually lead to vasoconstriction of dialation

Preload

Amount of blood in the heart at the end of diastole (EDV)

How to alter preload

Muscle pump, respiratory pump, venoconstriction

Afterload

Amount of resistance that the ventricle must overcome to eject blood (MABP)

MABP at rest

DBP +1/3 (SBP-DBP)

MABP during exercise

DBP + 1/2(SBP-DBP)

TPR=

MABP/CO

The number of CCBs is determined by…

1. CA2+ availability

2. Sarcomere length

SV equation

EDV-ESV

CO equation

HR x SV

EF equation

SV / EDV x 100