Intro to Human Phys - Ch 3: Cells and Tissues

cells

basic structural and functional unit of living and organisms

plasma membrane

barrier for cell contents (made of phospholipids with proteins to let things through)

tight junctions

zipper-like fusion that creates leakproof sheets

desmosome (anchoring) junction

“rivets” that anchor cells together and prevent cells from being pulled apart my mechanical stress

gap (communicating) junction

hollow cylinders of proteins form pores that allow small molecules to pass from cell to cell

nucleus

control center of the cell (contains genetic material aka DNA)

nuclear envelope (membrane)

a double membrane with nuclear pores and contains the nucleoplasm

nucleolus (-i)

one or more per nucleus, ribosomes assembly

chromatin

composed of DNA wound around histones, scattered throughout the nucleus when cell is not dividing. condenses and form chromosomes when cell divides

cytoplasm

contains cytosol (fluid that suspends other elements), organelles, and inclusions

ribosomes

site of protein synthesis and is made of protein and rRNA

endoplasmic reticulum

fluid tunnels that carry substances

rough ER

has ribosomes, manufactures all secreted proteins, creates membrane proteins and phospholipids.

smooth ER

lacks ribosomes and contains enzymes that function in liver, synthesis of steroid-based hormones, intestinal cells, and in skeletal and cardiac muscle which store and release calcium.

golgi apparatus

stack of flattened membranes that modifies, concentrates, and packages proteins and lipids (like UPS of cell)

lysosomes

membranous bags that contain digestive enzymes (acid hydrolases) which digest ingested bacteria, viruses and toxins. degrade nonfunctional organelles, and destroy cells in injured or nonuseful tissue (autolysis)

peroxisomes

membranous sacs of oxidase and catalase enzymes (detoxify harmful substances such as alcohol and formaldehyde)

cytoskeleton

provides the cell with an internal framework that determines cell shape, supports organelles, and directs intracellular transport. three types: microfilaments (smallest), intermediate filaments, microtubules (largest)

centrioles

generate microtubules and direct the formation of mitotic spindle during cell division

cilia surface extensions

little hairs that move materials across the cell surface (ex: on respiratory tract to move mucus)

flagella surface extension

tail that propels the cell (sperm is the only one with this extension)

microvilli surface extension

tiny finger-like extensions of the plasma membrane (increase surface area for absorption)

fibroblasts (connects body parts)

secretes cable-like fibers

erythrocyte (RBS) (connects body parts)

carries oxygen in the bloodstream

epithelial cells

cell that cover and line body organs

skeletal muscle and smooth muscle cells

cells that move organs and body parts

fat cells (adipocytes)

lipid droplets stores in cytoplasm, cell that stores nutrients

white blood cells

digest infectious microorganisms and fights disease

nerve cell (neuron)

receives and transmits messages to other body structures, gathers info and controls body functions

solutions

homogeneous mixture of two or more components

solvent

dissolves medium; present in the larger quality (H2O in the human body)

solutes

compounds in smaller quantities within a solution

intracellular fluid

nucleoplasm and cytosol

extracellular fluid

fluid outside of cell, mainly as interstitial fluid

membrane transport

movement into and out of cell

concentration gradient

measure of the difference of a solute between two points of a solution

movement down or with the concentration gradient

solute is moving from a higher to a lower concentration of solutes

movement up or against concentration gradient

solute is moving from a lower to a higher concentration and requires energy

passive process of membrane transport

substances are transported across the membrane without any input from cell

active process of membrane transport

the cell provides the metabolic energy (ATP) to drive the transport process

simple diffusion

unassisted movement of solutes

facilitated diffusion

transports lilid-insoluble substances, charged substances, and substances too large for passage through membrane pores. (uses membrane channels or protein molecules that act as carriers)

osmosis

simple diffusion of water across a selectively permeable membrane

tonicity

the ability of a solution to cause a cell to shrink or swell

isotonic solutions

equal amount of solute and water concentrations on both sides of membrane; cells gain and lose water at same rate

hypertonic solutions

water is drawn out of the cell because the solution contains more solutes

hypotonic solution

water is drawn into the cell because the cell contains more solutes

filtration

water and solutes are forced through a membrane by fluid pressure (like how a french press works)

simple diffusion passive transport

small lipid-soluble

carrier-mediated facilitated diffusion

lipid-insoluble

channel-mediated facilitated diffusion

ions and other molecules

active process membrane transport

ATP is used to move substances across a membrane

exocytosis vesicular transport

material is carried in a membranous sac called a vesicle that migrates to and combines with the plasma membrane, contents are emptied outside

endocytosis vesicular transport

extracellular substances are engulfed in a membranous vesicle, vesicle detaches from the plasma membrane and moves into the cell, once in cell will fuse with a lysosome

phagocytosis

cell engulfs large particles such as bacteria or dead body cells, protective mechanism

pinocytosis

cell “gulps” droplets of extracellular fluid containing dissolved proteins or fats

cell life cycle

series of changes a cell will experience from the time it is formed until it divides

interphase

cell grows and carries on metabolic processes

cell division

cell reproduces itself

DNA replication

A bonds to T and G bonds to C

mitosis

division of nucleus

cytokinesis

division of cytoplasm

prophase

nuclear envelope and nucleoli brake down and chromatin coils into chromosomes

metaphase

chromosomes are aligned in the center of the cell on the metaphase plate

anaphase

centromere splits and chromatids move slowly apart towards opposite ends of the cell

telophase

chromosomes uncoil and become chromatin, nuclear envalope re-forms around chromatin

gene

DNA segment that carries a blueprint for building one protein

RNA

contains U instead of T and is single stranded

rRNA

helps form the ribosomes where proteins are built

mRNA

carries the instructions for building a protein

tRNA

escorts appropriate amino acids to the ribosome for building the protien

transcription of protein synthesis

transfer of information from DNA’s base sequence to the complementary base sequence of mRNA

codon

three-base sequences on mRNA

triplets

three-base sequence of DNA

anticodon

three-base sequence of tRNA

epithelial tissue

cells that fit closely together to form sheets that cover and line surfaces of the body

simple epithelial

single layer

stratified epithelial

more than one layer of cells (function primarily in protection)

squamous cell

flattened cell (similar to fish scales)

cuboidal cell

cube-shaped cells

columnar cell

column shaped cell

pseudosstratified columnar simple epithelial cell

cells are different sizes but there is still only one layer of cells

transitional stratified epithelial cell

cells are able to change shape (stretch)

simple squamous epithelium

usually forms membranes that line air sacs, walls of capillaries, and serous membranes that line organs in ventral cavity.

simple cuboidal epithelium

common in glands and their ducts, forms walls of kidney tubules, and covers surface of ovaries

simple columnar epithelium

line the digestive tract from stomach to anus

mucous membranes

line body cavities that are open to the exterior

pseudostratified columnar epithelium

located in the respiratory tract, functions in absorption or secretion

stratified squamous epithelium

protective covering where friction is common, lining of the skin, mouth, and esophagus

stratified cuboidal epithelium and stratified columnar epithelium

rare in the body, found mainly in ducts of large glands

stratified transitional epithelium

functions in stretching and the ability to return to normal shape (founds in the lining of urinary bladder)

gland

one or more cells responsible for secreting a substance onto a surface, into a cavity, or into blood.

endocrine gland

ductless; secretions (hormones) diffuse into blood vessels (thyroid, adrenals, and pituitary)

exocrine glands

secretions empty through ducts to the epithelial surface (sweat and oil glands, liver, and pancreas)

connective tissue

functions: protection, supporting, cushioning, insulating

extracellular matrix

nonliving material that surrounds living cells

ground substance

mostly water, along with adhesion proteins and polysaccharide molecules

collagen (white) fibers

fibers that are tough and bendable

elastic (yellow) fibers

fibers that stretch

reticular fibers

fibers that form a mesh