human biology Flashcards
what does the nervous system do?
collects internal and external information
processes and responds to information
what is th nervous system composed of?
central nervous system, peripheral nervous system
central nervous system
brain and spinal chord
processes information and forms a response
peripheral nervous system
nerves
collects information using sense organs
responds to info using effectors muscles/glands)
nueron
receives and transmits information
made of: cell body, dendrite, axon, synapse
cell body
contains cell membrane, nucleus, other organelles
dendrite
short branches coming out of cell body
recieve signals from environment or other nuerons
axon
long tube extending from cell body
transmits nerve impulses
synapse
junction between synaptic terminals and a gland or muscle
neurotransmitter released from a neuron crosses to synapse and picked up by muscle or gland receptor
neurotransmitter
chemical that affects another cell
how is an impulse sent
due to selectively permeable axon membrane it is more permeable to potassium than sodium
at a resting state
outside the axon is more positively charged more sodium ions
inside is more negatively charged lots of negatively charged proteins and potassium ions
how was an impulse started
when it a stimulus reaches threshold meeting the minimum a stimuli required to cause action potential
action potential #1
causes axon membrane to open the sodium gates
sodium attracted to the negative charges inside the non-flood into it
outside becomes more negatively charged and inside becomes more positively charged
action potential #2
then that potassium ion gates and acts on membrane open due to excess sodium ions
the potassium ions are repelled by the positive charges and flood outside of the neuron
outside becomes more positively charged and inside becomes more negatively charged again
this swapping of potassium and sodium travels down the neuron in one direction away from the cell body
at the synaptic terminal the neurotransmitter is released making a reaction
what factors affect the nervous system
1.amount of myelination in axon More is a fast reaction 2. permeability of sodium on axon 3.type of neurotransmitter 4. Prescription drugs 5. Illegal drugs
Acetylcholine
muscle contraction
serotonin
sleep, mood, tension and learning
dopamine
movement reward
endorphins
reduce pain increase positive mood
what does heroin and codeine do?
increase dopamine release can cause a feeling of well-being convulsions, or death
marijuana and hashish results
depressed higher brain centers
induce anxiety free state hallucinations distortions of time and space
cocaine affects
keep dopamine in synapses for a long time creates euphoric feeling constrict blood vessels may cause death
what are the nonspecific defenses against as he is
barrier/innate defense- skin and mucous membranes
cellular defense-one bacteria viruses etc. get to scan barrier inflammatory response
skin mucous membranes
provide physical barrier
mucus trapped microbes cilia sweeps into stomach or out of body
lysozyme
antimicrobial found in saliva and mucus and tears
inflammatory response
triggers release of histamine-causes blood vessels to dilate
fluid squeezes through dilate blood vessels-causes pain temperature increases following
Phagocytes squeeze through dilated blood vessels-in golf or kill pathogens by phagocytosis
lymphatic system
recognizes self versus other and attacks the other based on protein tags
made of bone marrow, spleen, thymus, lymph nodes and lymphatic vessels
lymph vessels
network of thin tubes that carry lymph and white blood cells
lymph
fluid that transports foreign particles to lymph nodes
lymph nodes
enlarged bodies throughout lymphatic system clean and defend against infection
lymphocytes
white blood cells that circulate in blood and lymph
b and T cells
b cells
originate and mature in bone marrow
T cells
originate in bone marrow mature and thymus gland
plasma B cells
short-lived B cells
secrete antibodies that clump to antigens
memory B cells
long-lived B cells circulate for future immunity
respond quickly when exposed to same antigen again
how do T cells work
defend against viruses and bacteria without infecting body cells from thy protozoa and parasitic worms
helper T cells
recognize infected cells, stimulate B cell production, and stimulate cytotoxic T cells
cytotoxic T cells
recognize and destroy cells infected with pathogen, stimulate memory T cell production
memory T cells
long-lived T cells for future immunity, respond quickly when exposed to same antigen again
human supplements to natural body defense
antibiotics-kill bacteria
vaccines-use an active virus or bacteria to produce memory cells which quickly fired off the future infection
passive immunity-is transmitting antibodies from previously infected to newly infected person, mother to baby
endocrine gland
secrete hormones directly into the blood
exocrine gland
secrete substances onto a surface
hormone
chemical secreted by cell that affects a target cell
target cells
contains receptors receive secreted hormone
what is the role of the endocrine system
to maintain homeostasis
negative feedback system
1 gland shuts off if too much hormone in body
2 gland turns back on when not enough hormone in the body
positive feedback system
1 gland produces hormones
2 hormone stimulates glands to make more hormone
major hormones of the pituitary gland
located in brain
growth hormone, prolactin, anti-diuretic hormone, oxytocin
growth hormone
stimulates cells to increase in size and grow more rapidly
prolactin
stimulates sustained milk production in women after birth
anti-diuretic hormone
decreases urine production
oxytocin
contracts uterin wall muscles and milk secretion muscles
major hormones of the thyroid gland
located in neck region
thyroxin, calcitonin
thyroxin
increases metabolism and growth
calcitonin
takes calcium out of blood and stores in blood
parathyroid glands
four glands embedded and thyroid glands
parathyroid hormone-releases calcium from bone and puts it back into blood
adrenal glands
located on top of each kidney help deal with stress
produce: adrenaline, aldosterone, cortisol, adrenal androgens
adrenaline
responsible for a flight or fight response
aldosterone
controls electrolyte balance
cortisol
controls metabolism
adrenal adrogens
supplement sex hormones from gonads
pancreas
located in your small intestine, regulates blood glucose and blood
glucagon- elevated blood glucose levels
insulin-decrease blood glucose levels
pineal gland
located near basic brain and regulates circadian rhythms
thymus gland
located about heart, helps with immunity
ovaries
estrogen and progesterone that regulate menstrual and ovarian cycle
testes
testosterone regulates sperm production
placenta
regulates embryo/fetal development
