BIO 007 Midterm 5

steroid hormones

made from cholesterol

steroid hormone properties

hydrophobic lipids, can diffuse through plasma membrane, signal transduction

signal transduction

chemical communication thru cell

steroid hormone signal transduction steps

1. steroid hormone diffuses across cell membrane

2. binds to specific receptor protein inside the cell

3. receptor - hormone complex binds to target DNA

4. activates expression of target genes

non-steroid hormones

made from proteins, signal transduction

non-steroid hormone signal transduction steps

1. binds to receptor on surface of cell membrane

2. triggers signaling cascade

3. specific target proteins are activated by phosphorylation

pituitary gland

attached to and controlled by hypothalamus at base of brain

anterior pituitary gland

synthesizes own hormones

growth hormone (GH)

stimulates cell division, from anterior pituitary gland

prolactin (PRL)

stimulates milk production, from anterior pituitary gland

thyroid-stimulating hormone (TSH)

controls thyroid secretions, from anterior pituitary gland

adrenocorticotropic (ACTH)

controls hormones of adrenal cortex, from anterior pituitary gland

gonadotropins

hormones that affect reproductive hormones, from anterior pituitary gland

female follicle-stimulating hormone (FSH)

development of ovarian follicles (ovulation, production of estrogen), from anterior pituitary gland

male follicle-stimulating hormone (FSH)

stimulates production of sperm, from anterior pituitary gland

female luteinizing hormone (LH)

triggers ovulation, from anterior pituitary gland

male luteinizing hormone (LH)

stimulates production of testosterone, from anterior pituitary gland

posterior pituitary gland

releases hormones synthesized by hypothalamus

antidiuretic hormone (ADH)

causes kidneys to conserve water, from posterior pituitary gland

oxytocin (OT) in childbirth

uterine contraction, cervical dilation, from posterior pituitary gland

oxytocin (OT) in breastfeeding

milk ejection reflex in mammary glands, from posterior pituitary gland

oxytocin (OT) in maternal bonding

attachment, from posterior pituitary gland

oxytocin (OT) in social bonding

trust, empathy, generosity, from posterior pituitary gland

oxytocin (OT) in romantic attachment

love, from posterior pituitary gland

thyroid gland

attached in between larynx and trachea

T3 and T4

controls basal metabolic rate, goiter, from thyroid gland

basal metabolic rate (BMR)

amount of calories consumed at rest (activate genes for cellular respiration and regulate body heat production)

goiter

enlarged, protruding thyroid gland (occurs from iodine deficiency)

calcitonin

regulates calcium and phosphate in the blood, from thyroid gland

adrenal glands

on top of each kidney

adrenal medulla

inner layer

fight-or-flight response

epinephrine, norepinephrine, forced cardiac muscle contraction; increase in heart rate, breathing rate, blood glucose levels, blood pressure, decreased in digestive activity

epinephrine

adrenaline, from adrenal medulla

norepinephrine

noradrenaline, from adrenal medulla

adrenal cortex

outer layer

aldosterone

mineral corticoid, from adrenal cortex

aldosterone functions

regulates mineral electrolytes, causes kidneys to conserve sodium ions, levels to water retention by osmosis to maintain blood volume/pressure

cortisol

glucocorticoid, from adrenal cortex

cortisol functions

regulates glucose metabolism, gluconeogenesis, elevated under stress

gluconeogenesis

liver synthesizes glucose from amino acids and fatty acids (increase blood glucose levels)

pancreatic islets

islets of Langerhans

glucagon

stimulates liver to breakdown glycogen into glucose, raises blood sugar levels, prevents hypoglycemia, from pancreas

insulin

stimulates liver to form glycogen from glucose, promotes glucose uptake by adipose and muscles, stimulates adipose to synthesize and store fat, reduces blood sugar levels, from pancreas

Type I diabetes

loss of insulin producing cells

Type II diabetes

cells fail to respond to insulin

diabetes complications

1. high blood pressure increase blood viscosity due to elevated glucose levels

2. cardiovascular disease

3. vision loss

4. kidney damage

5. nerve damage

6. foot problems

7. decline in cognitive function

diabetes induced cardiovascular disease

heart attack stroke, damage to blood vessels

diabetes induced vision loss

damage to eye blood vessels

diabetes induced kidney damage

damage to glomerulus

diabetes induced nerve damage

numbness, tingling, pain

diabetes induced foot problems

poor circulation to extremities, loss of sensation in foot, can lead to unnoticed injuries

pineal gland

attached to part of your thalamus

melatonin

regulates circadian rhythm, from pineal gland

melatonin released when

retina receive no light input

melatonin maintains

day/night (sleep/wake) cycle, season cycles (fertility patterns in animals)

thymus

posterior to sternum between the lungs, relatively large within children but shrinks with age

thymosins

affect production and maturation of WBC, from thymus

T cell maturation

T cells form in bone marrow then migrate to thymus for positive/negative selection

positive selection T cell

T cell must show it can recognize the body’s self-identification tags

negative selection T cell

T cell must show it won’t attack the body’s own antigens

testosterone

produced in testes, found in ovaries and placenta

estrogen

found in ovaries and placenta

placenta

estrogen, progesterone, gonadotropin

physical stress

injury, disease, extreme temperatures, decreased oxygen, heavy exercise

psychological stress

emotional distress, personal loss, social interactions

stress response

general adaptive syndrome

immediate “alarm” stage stress

epinephrine, norepinephrine

immediate “alarm” stage steps

1. increase glucose and fatty acid in blood

2. increase heart rate and blood pressure

3. increase breathing rate

4. shunting blood from skin and digestive organs to skeletal muscles

5. preparing to “fight or flight”

long-term “resistance” stage stress

• stress hormones: fight or flight

• glucagon, growth hormone released to mobilize energy source

• antidiuretic hormone stimulates kidneys to retain water

stress hormones during long-term stress

1. hypothalamus secretes CRH

2. stimulates anterior pituitary gland to secrete ACTH

3. ACTH travels in bloodstream to adrenal glands

4. stimulates adrenal cortex to release cortisol

glucagon/growth hormone during long-term stress

• increase blood levels of amino acids and fatty acids

• glucose formed from non-carbohydrate sources

antidiuretic hormone during long-term stress

maintain blood pressure even if bleeding or sweating heavily

exhaustion - chronic health effects

• decreased number of WBC

• Lowers resistance to infection and cancer

• increase risk of high blood pressure, atherosclerosis, ulcers, etc.

neuron

transmits information by electrical impulses

neuron impulse

electrical charge

neuron cell body

main part of the cell

neuron dendrites

extensions that receive info

neuron axon

extension that sends info

neuron hillock

cone-shaped thickening that leads to axon

myelinated axon

has myelin sheaths

nodes of ranvier

gaps

white matter

myelinated axons of central nervous system (CNS)

Unmyelinated neuron

no myelin sheaths

gray matter

unmyelinated axons of CNS

multipolar neuron

multiple extensions (many dendrites, one axon)

bipolar neuron

two extensions (1 dendrite, 1 axon)

unipolar neuron

one extension (one side dendrite, other side axon)

sensory neuron

afferent neuron

sensory neuron properties

receive input from peripheral body parts from sensory receptors, most are unipolar, some are bipolar

Interneurons

found in brain and spinal cord

interneuron properties

conduct impulses from one part of brain/spinal cord to another, multipolar

motor neuron

efferent neuron

motor neuron properties

conduct impulse from brain/spinal cord to muscle, multipolar

neuroglia

“nerve glue”, nourish and support neurons

microglial cells

phagocytose bacteria and cellular debris, bloodborne immune cells have limited access to CNS

oligodendrocytes

provide insulating myelin sheath around axons in CNS

schwann cells

provide insulating myelin sheath around axons in Peripheral nervous system (PNS)

astrocytes

found between blood vessels and neurons of CNS, regulate nutrient flow

astrocytes have blood brain barrier where

chemicals flowing into brain are highly regulated

satellite cells

control chemical environment and nutrient flow to neurons of PNS