Exam 2

• Blood hormone concentrations

  effect of hormone on tissue- plasma concentration and number of active receptors

  quantity of transport proteins

  changes in plasma volume
• Magnitude of hormone effect depends on:

  concentration of the hormone

  number of receptors on the cell

  affinity of the receptor for the hormone
• Downregulation

  decrease in receptor number in response to high concentration of hormone
• Upregulation

  increase in receptor number in response to low concentration of hormone
• Second messengers

  activated in cell via G protein
• Growth hormone

  stimulates release of insulin-like growth factors- IGFs

  essential growth of all tissues- amino acid uptake and protein synthesis

  spares plasma glucose- increases gluconeogensis and mobilizes fatty acids
• ADH


  posterior pituitary gland

  reduces water loss to maintain plasma volume

  stimulated by high plasma osmolality
• Aldosterone


  control of Na reabsorption and K secretion

  regulation of blood volume and pressure- renin-angiotension-aldosterone system
• Insulin


  pancreas

  storage of glucose, fats, and amino acids

  stores fuels and lowers blood glucose

  decrease during exercise
• Glucagon

  pancreas

  increased FFA mobilization

  increase gluconeogenesis

  decreased glycogen uptake

  increases with exercise
• Cortisol

  adrenal cortex

  increased FFA mobilization and gluconeogenesis

  decreased glucose uptake

  mobilizes fat fuels and preserves glucose uptake

  decreases during exercise
• Epinephrine and norepinephrine

  adrenal medulla

  increase muscle and liver glyconeogenesis

  increase FFA mobilization

  fat and carb fuels

  increases during exercise
• Slow acting hormones

  thyroxine

  cortisol

  growth hormone
• Fast acting hormones

  epinephrine

  norepinephrine

  insulin

  glucagon
• Plasma glucose maintained through:

  mobilization of glucose from liver glycogen stores

  mobilization of FFA from adipose tissue

  gluconeogenesis from amino acids, lactic acid, and glycerol

  blocking entry of glucose into cells
• Leukocytes

  Neutrophils- phagocytosis; release chemicals involved in inflammation

  Basophils- release chemicals involved in inflammation

  Eosinophils- destroy parasites, hypersensitivity reactions

  Monocytes- precursors of macrophages
• Lymphocytes

  B cells- secrete antibodies- acquired immunity

  T cells- killer, helper, regulatory- acquired immunity

  Natural killer- direct binding to infected cells
• Innate immune system

  physical barriers

  phagocytes- macrophages and neutrophils

  natural killer cells

  complement system
• Acquired immune system

  B cells

  T cells- killer, helper, regulatory
• Open window theory

  may be caused by high cortisol levels + lack of sleep, mental stress, and increased exposure to pathogens
• Peripheral nervous system


  sensory division- afferent- towards CNS

  motor division- efferent- to effector organ
• Autonomic nervous system


  sympathetic- releases norepinephrine

  parasympathetic- releases acetylcholine
• Resting membrane potential

  negative charge of cells at rest

  determined by permeability of plasma membrane to ions and difference in ion concentration across membrane

  maintained by the sodium potassium pump- 2 K in, 3 Na out
• Action potential

  when stimulus of sufficient strength depolarizes the neuron

  opens Na channels, diffuses into cell
• EPSP

  excitatory postsynaptic potentials

  promote neural depolarization by temporal summation (one presynaptic neuron) or spatial summation (several different presynaptic neurons)
• IPSP

  inhibitory postsynaptic potentials

  cause hyperpolarization
• Joint proprioceptors

  free nerve endings

  golgi type receptor

  pacinian corpuscles
• Muscle proprioceptors

  muscle spindles

  golgi tendon organ
• Free nerve endings

  sensitive to touch and pressure
• golgi type receptor


  found in ligaments and around joints
• Pacinian corpuscles

  located in tissues around joints

  detect rate of joint rotation
• Muscle spindle

  changes in muscle length:

  intrafusal fibers- run parallel to normal muscle fibers

  gamma motor neurons- stimulate intrafusal fibers to contract with extrafusal fibers

  stretch reflex:

  stimulates muscle spindles and promotes a reflex contraction

  stimulation of alpha motor neuron causes muscle to contract and resist being stretched
• Golgi tendon organ

  monitors force development in muscle

  stimulation results in reflex relaxation of muscle- IPSP sent to alpha motor neurons

  inhibition of alpha motor neurons cause muscle relaxation which relieves tension applied to the tendon
• Chemoreceptors

  sensitive to changes in chemical environment surrounding muscle fibers and provide the CNS with info about muscle metabolism
• Motor unit

  motor neuron and all the muscle fibers it innervates
• Innervation ratio

  number of muscle fibers per motor neuron

  low ratio= fine motor control

  higher ratio= do not require fine motor control
• Recruitment pattern

  type S --> type FR (2 a) --> type FF (2 x)
• Epimysium

  surrounds the entire muscle
• Perimysium


  surrounds bundles (fasicles)
• Endomysium

  surrounds individual fibers