regulation (f1 bio)

adaptation

changing genotype, changing phenotype

• genetic variation

• role for the environment

• long term (between generations, affects species/population)

evolution

population genotypes and phenotypes change over time

variation

genotypic differences result in phenotypic differences

selection

environmental pressures affect reproduction

acclimation

short term (within generation, affects individual)

• phenotypic plasticity

• regulated gene epxresion

• role for environment

endocrine system

• homeostatic regulation of other physiological systems

autocrine signals

act on same cell and secretes them

not very efficient

paracrine signals

diffuse locally and act on neighboring cells

endocrine signals

hormones carried between cells by blood or other body fluids

neural signals

diffuse a short distance between neurons

neuroendocrine signals

released from neurons but are carried by blood or other body fluids and act on distant cells

pheromones

released into the environment and act on a different individual

hypothalamus

antidiuretic hrmone (ADH)

promotes reabsorption of H2O by kidneys

ACTH (adrenocortiotropic hormone)

stimulates adrenal glands to secrete glucocorticoids such as cortisol

epinephrine

produces effects related to short term response

HPA axis

• hypothalamic pituitary adrenal axis

• regulates stress response

cortisol

ACTH, adrenal cortex —> produces glucocorticoids

amplification of hormonal signal

signaling cascade

not in one cell, in many!

negative feedback loop

• homeostasis

• stop signal by stopping the production of the signal

• more cortisol —> negatively affects HPA axis to stop releasing hormones

regulation of blood sugar

• hormones: insulin and glucagon

type 1 diabetes

• juvinile, insulin dependent

• insufficient insulin - deficiency of siignal

• autoimmune destruction of endocrine cells in pancreas (beta cells in islets of langerhans)

type 2 diabetes

• decreased responsiveness to insulin signaling → deficiency of receptor

• lipid-mediated/increase in protein kinase C activity reduces efficiency of signaling from insulin receptor

pancrease

insulin and glucagon expression limited to this

glucagon receptors

• binds to gpcr receptor (g protein coupled)

• signal cascade

• amplification done by secondary messenger AND kinases

insulin receptor

• tyrosine receptor kinase (dimer)

• regulation by alternative splicing

glucagon signaling

• low glucose level seen by pancreas

• glucagon stimulates to increase blood glucose

• negative feedback to pancreas to no longer release glucagon

hyperthyroidism

hormone: thyroxine

• effects: increased basal metabolic rate, increased heat production, increased sensitivity to adrenaline

• symptoms: weight gain, increased heart rate, hair loss, sweating, nervousness

• treatment: dietary (eat iodine), radioactive iodine, beta blockers, surgery

thyroxine synthesis

• tyrosine: chemical basis of thyroxines

• iodine: unique use of this element in physiology

• selenium: cofactor in enzymes used to convert T4 into active hormone

increases HR, increases

sensory neuron

• dendrites (top)

• cell body (middle)

• axon (bottom)

interneuron

more dendrites

connected to thousands of neurons

motor neuron

astrocytes

care and protection of neurons

oligodendrocytes and schwann cells

forms myelin sheaths

ependymal cells

produces cerebrospinal fluid

microglial cells

acts as immune cells

Na+/K+ pump

direction of ion flow

energy used

regulated by

K+ channel

direction of ion flow

energy used

regulated by

voltage gated Na+ channel

direction of ion flow

energy used

regulated by

Voltage gated K+ channel

direction of ion flow

energy used

regulated by

voltage gated Ca2+ channel

direction of ion flow

energy used

regulated by

voltage gated (forgot)

direction of ion flow

energy used

regulated by

action potential

• resting potential (-70) → voltage gated Na+ channels open and Na+ enters cell causing positive spike in membrane potential (positive inside relative to outside) → (electrical gradient brings to 0 but chemical brings it to +40) → at +40mV, Na+ channels close and voltage gated K+ channels open which allows K+ ions to leave cell and causes membrane potential to become more negative → overshoot in amount of K+ ions that leave the cell causes cell membrane to be hyperpolarized (leading to refractory period where nerve can’t fire another action potential) → membrane gradually returns to resting (Na+/K+ pump) as excess K+ ions are returned to cell AND potassium channel changes direction it moves potassium

axon helic