Anatomy Test #2

Chapters 3 & 4

cell

structural & functional unit of life

fibroblast

• found in connective tissues

• responsible for creating and maintaining the structural framework of the body

erythrocytes

• anucleate RBC’s

• responsible for carrying oxygen from the lungs to the body's tissues

epitheleal cells

• found in linings and glands

• tightly packed cells that form protective outer layers

adipocyte

• fat cell used for storage

• energy, insulation

macrophage

• immune cell (WBC)

• destroys pathogens (phagocytosis), cellular debris, and foreign substances

spermatozoon

• mature, motile male reproductive cell

• only human cell w/ flagellum

skeletal muscle cell

• multinucleate, long, cylindrical, and striated cells

• attach to your skeleton to control voluntary body movements

smooth muscle cell

• spindle-shaped, involuntary

• control automatic movements

nerve cell

• transmit electrical and chemical signals throughout the body

3 basic parts of a cell

1. plasma membrane

2. cytoplasm

3. nucleus

plasma membrane

barrier separating the inside of a cell from the outside

structure of plasma membrane

• lipid bilayer

• fluid mosaic pattern

• surface sugars (glycocalyx)

• cell junctions

integral membrane proteins

• inserted into membrane

• hydrophilic/hydrophobic regions

peripheral membrane proteins

• loosely attached to integral proteins

• filaments used for plasma membrane support

functions of membrane proteins

1. transport

2. receptors for signal transduction

3. attachment to cytoskeleton & extracellular matrix

4. enzymatic activity

5. intercellular joining

6. cell-to-cell recognition

tight junction

prevents fluids and most molecules from moving between cells

desmosomes

• “spot welds” that anchor cells together

• allows give between cells

gap junction

transmembrane poroteins form pores that allow small molecules to pass from cell to cell

diffusion (passive)

collisions between molecules in areas of high concentration cause them to be scattered into areas w/ lower concentration

simple diffusion

nonpolar, lipid-soluble (hydrophobic) substances diffuse directly through the phospholipid bilayer (ex: oxygen, carbon dioxide)

facilitated diffusion

certain hydrophbic molecules are transported passively down their concentration gradient

carrier-mediated diffusion (type of facilitated diffusion)

substances bind to protein carriers that carry specific molecules

channel-mediated diffusion (type of facilitated diffusion)

substances move through aquaporins

leakage channels

always open

gated channels

controlled by chemical/electrical signals

osmosis

movement of solvent across a selectively permeable membrane (through lipid bilayer or aquaporins)

when does osmosis occur?

when solvent concentration is different of 2 sides of a membrane

hydrostatic pressure

pressure of solvent inside cell pushing on membrane

osmotic pressure

tendency of solvent to move into cell by osmosis (more solutes in cell = higher osmotic pressure)

tonicity

ability of a solution to change shape/tone of cells by altering the cell’s internal H₂O volume

isotonic solution

same osmolarity as inside of cells, so volume is unchanged (H₂O movement at equilibrium)

hypertonic solution

has higher osmolarity than inside of cell, H₂O flows out of cell (cell shrinks/crenation)

hypotonic solution

has lower osmolarity than inside of cell, H₂O flows into cell (cell swells/lyses)

what solution would you give to someone to quickly raise their blood volume?

isotonic solution

what solution would you give to someone who is edamatous (swollen) to pull H₂O into blood?

hypertonic solution

what solution should you generally not give to someone?

hypotonic solution

why would active transport occur (3 reasons)

1. solute is too large for channels

2. solute isn’t lipid soluble

3. solute isn’t able to move down the concentration gradient

active transport (requires ATP)

• requires carrier proteins that bind specifically/reversibly w/ the substance being moved

• moves solute against concentration gradient

vesicular transport (requires ATP)

transports large particles within cell (uses vesicle)

endocytosis (vesicular transport)

transport into cell

phagocytosis (endocytosis/vesicular transport)

membrane projections form vesicle around particles, “cell eating”

which types of cells use phagocytosis?

macrophages and certain WBC’s

pinocytosis (endocytosis/vesicular transport)

plasma membrane unfolds, bringing fluid and dissolved solutes inside of cell , “cell drinking”

exocytosis

material is ejected from cell (ejected material enclosed in secratory vesicle

where is exocytosis used?

hormones, neurotransmitters, waste

cytoplasm

cellular material located between plasma membrane and nucleus

cytosol

gel-like solution made up of H₂O and soluble molecules

mitochondria

• produce most of cell’s energy (ATP) via aerobic cellular respiration

• have their own DNA, RNA, and ribosomes

ribosomes

• nonmembranous, site of protein synthesis

• made of protein and rRNA

rough ER

site of synthesis of membrane proteins and phospholipids

smooth ER

enzymes found in membrane function in lipid metabolism, absorption, synthesis, transport of fats, detoxification fo drugs/pesticides, converting glycogen to free glucose, storage/release of calcium

Golgi apparatus

modifies, concentrates, and packages proteins/lipids

lysosomes

• isolate potentially harmful intracellular digestion from rest of cell

• digest bacteria, viruses, and toxins

• degrade non-functional organelles

peroxisomes

detoxifies free radicals

free radicals

toxic, highly reactive, natural byproducts of cellular metabolism, can cause damage if not detoxified

oxidase

uses oxygen to convert toxins to H₂O₂ (also toxic)

catalase

converts H₂O₂ into water

cytoskeleton

rods that run through cytosol, plays role in movement of cell components

microfilaments

thinnest, semi-flexible strands of actin (involved in cell motility, changes in shape, or endo/exocytosis

microtubules

determines overall shape of cell and distribution of organelles

motor proteins

complexes that function in motility, powered by ATP

centrosome

located near nucleus, area where centriole is located

centrioles

form basis of cilia and flagella

cilia

whip-like, motile extensions on surfaces of certain cells (move substances across cell surface)

microvilli

finger-like projections that extend surface of cell to increase surface area for absorption

flagella

extensions that propel cell (sperm)

nucleus

genetic library of blieprint for synthesis of cellular proteins

which cells are multinucleate?

skeletal muscle, certain bone cells, some liver cells

what cells are anucleate

RBC’s/erythrocytes

3 main structures of nucleus

1. nuclear envelope

2. nucleoli

3. chromatin

nuclear envelope

double membrane (outer is continuous w/ rough ER, inner is called nuclear lamina)

nucleoplasm

jelly-like fluid in nucleus

nuclear lamina

network mesh of proteins, scaffolding for DNA

nuclear pores

allow substances to pass in/out of cell

nucleoli

responsible for rRNA synthesis/ribosome unit assembly, 1-2 per nucleus

chromatin

30% strands of DNA, 60% histone proteins, 10% RNA

nucleosomes

fundamental unit of chromatin (DNA wrapped around histones)

chromosomes

condensed chromatin

interphase

period from cell formation to cell division, preparation for division (where the cell spends 95% of its time)

G₁ phase

vigorous growth and metabolism

S phase

DNA replication (synthesis)

G₂ phase

preparation for division

DNA polymerase

attaches to RNA primer strand and adds nucleotides to form new strands

leading strand

synthesized continuously

lagging strand

synthesized discontinuously into segments and spliced together by DNA ligase

semiconservative replication

each new double-stranded DNA is composed of 1 old strand and 1 new strand

helicase

unzips DNA

which cells don’t divide efficiently?

skeletal, cardiac, and nerve cells

early prophase

• chromatin condenses

• centrioles migrate to poles of cell

late prophase

• nuclear envelope disappears

• spindle attaches to centromere

metaphase

• centromeres align on cell equator (metaphase plate)

anaphase

• shortest

• centromeres split, chromosomes pulled towards poles

telophase

• begins when chromosome movement stops

• chromosomes uncoil

• nuclear membrane reforms

• spindle disappears

cytokinesis

• begins during anaphase

• cleavage furrow forms and cells pinched apart

go signals for cell division

• surface-to-volume ratio of cell (cell divides when it gets too big

• chemicals (growth factors, hormones)

stop signals for cell division

availability of space (overcrowding/contact inhibition)

genetic theory

cessation of mitosis and cell aging are programmed into genes

telomeres

strings of nucleotibes that protect the ends of chromosomes, act like hourglass of how many times cells divide

telomerase

enzyme that lengthens telomeres