Chapter 4 Flashcards Preview

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Flashcards in Chapter 4 Deck (89):
1

nucleus

only in eukaryotes ; DNA can only be the in the nucleus

2

nuclear envelope

wraps the nucleus

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nucleolus

where rRNA is transcribed and the subunits of ribosomes are assembled

4

endocytosis

how cells can acquire substances from the extracellular environment

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phagocytosis

a few cells are capable of this , proteins binding on the particular matter to protein receptors on the phagocytotic cell

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pinocytosis

ECF engulfed by small invaginations of the cell membrane, performed by most cell and it is a random process

7

receptor mediated endocytosis

specifiic uptake of macromolecules, ligand binds to a receptro protein on the cell membrane and is then moved to a clathrin coated pit, the pit invaginates to form a coated vesicle, this process absorbs the ligands

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exocytosis

reverse of endocytosis

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phospholipid bilayer

membrane invaginates and forms individual membrane bound organelles

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ER

separates the cytosol from the ER lumen, in many places it is contiguous in places with the space between the double bilayer of the nuclear envelope

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rough ER

ER near the nucleus that has ribsomes attached,

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Golgi appartus

series of flattened membrane bound sacs, transport vescicles bud off from the ER and carry the proteins from the ER to the Golgi appartus, organizes and concentrates the proteins as they shuttled by tansport vesicles progressively outward from compartment or cisterna of the Golgi to the next. Golgi may change proteins chemically by glycosylation or by removing AA. end product is a vesicle full of proteins. can be released to mature into proteins or transported to other parts of the cell, secretory vesicles form the protein filled vesicles are expelled from the cell,

13

secretory vesicles

may contain enzymes, growth factors, or ECF matrix components , release contents through exocytosis, supply membrane with its integral proteins and lipids and as the mechanism for membrane expansion. regulated secretion--only release in response to a certain stimulus, some proteins are activated within the secretory vesicles

14

lysosomes

contain acid hydrolases--can break down every major type of macromolecule, have interior pH of 5 , fuse with endocytotic vesicles and digest their contents, any material not degraded by lysosomes is ejected by the cell. Autolysis-- lysosome bursts and kills the cell

15

smooth ER

resembles flattened sacs, contains glucose-6-phosphate which is hydrolyzed to glucose. triglycerides are produced in smooth ER and stored in fat droplets, phospholipids are orginially synthesized there

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adipocytes

cells contains predominately fat droplets

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peroxisomes

vesicles in the cytosol, grow by incorporating lipds and proteins from the cytosol, self -replicate, produce and breakdown hydrogen peroxide , inactivate toxic substances, regulate ocygen concentration, play a role in the synthesis of breakdown of lipids, and in tthe metabolism of nitrogenous bases and carbohydrates

18

cytoskeleton

structure and motility of a cell is determined by a network of filaments

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microtubles and microfilaments

microtubules are larger than microfilaments;rigid hollow tubes from a protein called tubulin; 13 of these filaments lie alongside each other to form the tube

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mitotic spindle

made from microtubules

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flagella and cilia

specialized structures also made from microtubules

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axoneme

the major portion of each flagella and cilium, contains 9 pairs of microtubules forming a circle around 2 lone microtubules in an arrangement 9+2

23

crossbridges

made from dynein connect each of the outer pairs of microtubules to their neighbor,cause microtubule pairs slidge along their neighbors creating a whip action in cilia causing fluid to move laterally, or a wiggle action in flagella causing fluid to move directly away from the cell

24

MTOC in animal cells

centrosome

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centrioles

function in the production of flagella and cilia

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Actin

major component of microfilaments

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microfilaments

contracting force in muscle as wll as being active in cytoplamic streaming (responsible for amoeba-like movement), phagocytosis and microvilli movement

28

tight junctions

form a watertight seal from cell to cell that can block water, ions and other molecules from moving around and past cells, --complete fluid barrier, hold together epithelial tissue in organs , barrier to protein movement between the apical and the basolateral surface of a cell

29

desmosomes

two cells at single point, attach directly to the cytosketeleton, don't provent fluid from circulating, found in tissues that normally experience a lot of stress

30

gap junctions

small tunnels connecting cells, allow small molecules and ions to move between cels, in cardiac muscle provide for the spread of the action potential from cell to cell

31

mitochondria

own circular DNA that replicates independently from the eukaryotic cell, no histones or nucleosomes genes in mitochondrial DNA code for mitochondrial RNA that is distnct from the RNA in the rest of the cell, DNA passed maternally even in organisms whose male gamete contributes to the cytoplasm

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endosymbiont theory

mitochondria may have evolved from a symbiotic relationship between ancient prokaryotes and eukaryotes

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mitochondria

surrounded by 2 phospholipid bilayers; inner membrane -- invaginates to form cristae, inner membrane that holds the electron transport chain, between inner and outer membrane in the intermembrane space

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Tissue

cells that work together for a common purpose-- epithelial tissue, muscle tissue, connective tissue and nervous tissue

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Extracellular Matrix

constitute most of the tissue as in bone, surrounds the cell and that is formed by the cell itself

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epithelial tissue

simple -- one layer thick, stratified -- two or more layers thick

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connective tissue

blood, lymph, bone cartilige,

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neuronal communication

rapid, direct, specific

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hormonal comunication

slower, spread throughout the body, affects many cells and tissues in many different ways

40

inerstital fluid

where local mediators are released

41

neuron

functional unit of the nervous system is the neuron ; send electrical signal from one cell to another

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dendrites

recieve signal to be transmitted

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axon hillock

where the signal goes next then the axon if th esignal is strong enough and then to the synapse

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depolarization

cell becomes positive on the inside -- sodium channels open

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repolarization

sodium channels are closing, potassium channels opening cells becomes negative a gain

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hyperpolarization

potassium channels take longer to close so for a brief period the cell is more negative than its resting potential

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all-or-nothing

the membrane completely depolarizes or no action potential is generated

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threshold stimulus

stimulus of the membrane must pass this

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synapse

how neural impulses are passed from one neuron to another either chemically or eletrically

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electrical synapse

uncommon; gap junction between cells -- cardiac muscle -- very fast

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chemical synapse

unidirectional; small vesicles with neurotransmitter in the presynaptic membrane; AP comes, Calcium voltage channels open; calcium flows into cell--neurotransmitter vesicles release in the synaptic cleft ; then postsynaptic neuron becomes permeable to the neurotransmitters

52

Brownian Motion

how the neurotransmiter diffuses across the synaptic cleft (random motion of the molecules)

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neurotrasmitter

attaches to its receptor for only a fraction of a second and is released back into the synaptic cleft; either excites or inhibits not both

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second messenger system

activating another molecule inside the cell to make changes -- receptors

55

EPSP or IPSP

change in cell potential due a synapse

56

microglia

arose from white blood cells -- phagocytize microbes and cellular debris in the CNS

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ependymal cells

epithetial cells that line the space containing the cerebrospinal fluid -- use cilia to circulate the cerebro spinal fluid

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satellite cells

support ganglia

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astrocyes

star shaped neuoglia in the CNS , physicial suppor to neurons, maintain minerals and nutrient balance in the interstital space

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oligodendrocyes

wrap around axons creating myelin sheeaths

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Schwann cells

produce myelin in the PNS

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myelin

increases the rate at which an axon can trasmit signals -- white matter or grey matter; only in vertebrates

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nodes of Ranvier

gaps between myelin

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saltatory conduction

AP jumping from one node of Ranvier to the next

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sensory (afferent) neurons

recieve signals from the receptor cells that interacts with its environment then transfers this signal to other neurons; 99% of sensory input is discarded by the brain; located dorsally from the spinal cord

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interneurons

transfers signals from neuron to neuron

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motor (efferent) neurons

carry signals to a muscle or a gland called the effector, located near front of the spinal cord

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nerves

neuron process bundled together

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CNS

brain and spinal cord -- integrate nervous signals between sensory and motor neurons

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PNS

everything else -- handles senstory and motor function of the nervous system

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somatic nervous system

respond to external enviornment -- contains senstory and motor function, its motor neurons innervate only skeletal muscle -- neurons are located in the ventral horns of the spinal cord, located in the dorsal root ganglion

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autonomic nervous system

recieves signal from the viscera

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sympathetic NS

fight of flight; cell bodies found in spinal cord ; epinephrine or norepinephrine

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parasympathetic NS

rest or digest ; cell bodies found in brain and spinal cord ; cell bodies of postganglionic neurons lie in ganglia inside or near their effectors; use acetylcholine

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lower brain

medulla, hypothalamus, thalamus, cerebellum -- respriatory system, arterial pressure, salivation, emotions and reaction to pain and pleasure

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higher brain

cerbrum and cerebral cortex -- cerebral cortex can't function w/o the lower brain -- contains memories and thoughts

77

sensory receptors

physical stimulus to neuraal signals ,

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cornea

where light first strikes the anterior cavity

79

lens

suspensory ligaments tug on lens on faltten it -- connected to the ciliary muscle

80

retina

covers back of the eye has rods and cones -- rods have rhodopsin -- eye cell hyperpolarizes after the photon hits

81

cones

color

82

iris

colored portion of the ye that creates the opening called the pupil, in the dark sympathetitic NS, contracts the iris and dilates the pupil allowing more light to enter; bright environment contracts iris constricts pupil

83

ear

outer, middle, inner ear

84

tympanic membrane

external auditory canal carries the wave to the ____ or eardrum

85

middle ear

mallus, incus and stapes, act as a lever system -- increase force allows wave to be transferred from the air in the outer ear to a more resistant fluid within the inner ear

86

cochlea

wave of the inner ear moves to the ___- to the center of the sprial then spirals back out

87

hair cells ; organ of Corti

detects movement of wave and tranduces them to neural signals -- hair actually is microvilli that detect movement

88

semicircular canals

in the inner ear; responsible for balance ; each canal contains fluid and hair cells

89

taste

bitter; sour; salty and sweet