Week 1 - Cells & tissues Flashcards
what are the 3 major parts of cell?
- plasma membrane
- cytoplasm
- nucleus
what are the 2 major roles of plasma membrane?
- separates internal cellular components from external environment
- regulates movement of substances into and out of cell
fluid mosaic model
describes structure of plasma membrane
membrane lipids include what 3 parts and describe their characteristics?
- phospholipids (form lipid bilayer)
- cholesterol (straighten membrane)
- gycolipids (performs functions on membrane’s outer surface)
what are the major components of plasma membrane?
lipids and proteins
membrane proteins include?
- integral proteins (primarily transmembrane protein, ex. glycoproteins) and lipid-linked proteins
- peripheral proteins (located on outer surfaces of phospholipid bilayer, ex. glycocalyx)
what are the 6 functions of membrane protein?
- form ion channels (substances pass into or out of cell)
- transporters or carriers
- receptors (ligands)
- enzymes
- linkers
- cell-identity markers
what are the various fluids that substances move to and from cells?
- intracellular fluid (ICF) or cytosol
- extracellular fluid (ECF):
- interstitial/intercellular fluid (b/t cells of tissues)
- plasma (blood vessel)
- lymph (lymphatic vessels)
how does substances move across plasma membrane?
- passive processes
- active processes
- vesicular transport
which process describes: substance move across plasma membrane due to their own kinetic energy, DOWN a concentration gradient?
passive process
Osmosis
Facilitated diffusion
In active transport…?
substances move across a plasma membrane due to energy provided by ATP, AGAINST concentration gradient
describe vesicular transport
energy (from ATP) is expended so that vesicles either detach from plasma membrane to import sub into cell or fuse to export
In which organelle does this occur: cytosol is intracellular fluid in which organelles are suspended and in which solutes are dissolved and is the site of metabolic reactions, transport of sub, etc…
cytoplasm
what is cytoskeleton?
network of 3 types of protein filaments that provide shape to cell and play roles in cell movement as well as movements of organelles within cells
what are the 3 types of protein filaments that make up cytoskeleton and name their characteristics?
- microfilaments/microvilli
- microtubules: determine cell shape and function in intracellular transport of organelles -> important component of flagella, cilla, centrioles, mitotic spindle
- intermediate filaments: help position organelles as well as strengthen and give shape to cell
organelles
intracellular structures that have characteristic shapes and perform specialized functions
what is function of centrosomes (centrioles)
-aligns cells to prepare for mitosis
ribosomes
- organelles where protein synthesis occurs
what are the 2 types of endoplasmic reticulum (ER)?
- rough ER: studded with ribosomes that synthesize proteins destined to be secreted or delivered to lysosomes or to plasma membrane
- smooth ER: no ribosomes, but are sites for lipid synthesis, toxin detoxification, calcium storage in muscle cells, etc.
golgi complex
- cisternae (folds)
- receives proteins and lipids from rough ER
- modifies, sorts, packages these proteins and lipids into vesicles for delivery to lysosomes, the plasma membrane or to be secreted
lysosomes
- spherical membrane-enclosed sacs that form from Golgi complex
- contain numerous digestive enzymes -> autophagy (intracellular digestion), or autolysis (cell death)
peroxisomes
- detoxify cell (important in liver & kidney cells)
proteasomes
- detoxify cells
- contain proteases used for destruction of cytosolic proteins
why are mitochondria called the “powerhouse” of cells?
bc they produce, via cellular respiration, large quantities of energy-rich ATP molecules used to provide energy for cellular processes
which membrane-enclosed organelle is often sausage-shaped and self-replicates?
mitochondria
what are the 3 types of passive process?
- diffusion: down concentration gradient w/o aid from other things
- osmosis
- facilitated diffusion: move with aid of transporter protein
what are the 3 types of vesicular transport?
- endocytosis: receptor-mediate endocytosis; phagocytosis; pinocytosis
- exocytosis: secretory vesicles
- transcytosis: sub are moved by vesicles into a cell on one side, across the cell, then out of cell on other side
where is centrosome located and describe its shape?
-located near nucleus and consists of pair of centrioles (rt angle from each other)
what is the largest organelle that is usually spherical or oval-shaped?
nucleus
what is anucleated?
erythrocytes
what is an example of multinucleated cell?
skeletal muscle cells
how many genes in human genome?
30,000
nucleus contains 1 or more spherical nucleoli, what happens here?
subunit of ribosomes are produced
chromatin is located where, and chromatin is composed of?
inside nucleus, and chromatin is composed of DNA and associated proteins called histones organized into nucleosomes
what is arranged along the chromosomes in the nucleus, and what is it?
genes, which are the units of hereditary information
what is the total genetic information in a cell?
genome
when certain cells undergo orderly, genetically programmed death during embryological, fetal, and postnatal development, what is it called?
apoptosis
how is apoptosis triggered?
by intracellular or extracellular agents that induce activation of enzymes by “cell-suicide” genes
how to apoptosis cause cell death?
these enzymes damage cytoplasmic components
how does apoptosis differ from NECROSIS?
necrosis is a pathological type of cell death that results from tissue injury
what are the 4 major families of tissues that the body is composed of?
- epithelial
- connective
- muscular
- nervous
which tissue covers body surfaces, lines hollow organs, body cavities, and ducts, and also forms glands?
epithelial tissue
which tissue protects and supports the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity?
connective tissue
which tissue generates physical force for movement and thereby generates body heat?
muscular tissue
which tissue detects changes in a variety of conditions and responds by initiating and transmitting nerve impulses (signals) that help control and coordinate body activities?
nervous tissue
what are cell junctions?
points of contact b.t neighboring plasma membranes
what are the 5 major types of cell junctions
- tight junctions
- adherens junctions
- desmosomes
- hemidesmosomes
- gap junctions
which junction prevent the passage of substances b.t cells?
tight junctions
which junction forms tight seals b.t cells such as the epithelial cells that comprise the inner lining of stomach, intestines, and UB?
tight junctions
which junction helps epithelial surfaces resist separation?
adherens junctions
which junction prevents epidermal cells from separating under tension?
desmosomes
which junction prevents cardiac muscle cells from pulling apart during contraction?
desmosomes
which junction strongly anchor cells to an underlying basement membrane?
hemidesmosomes
which junction is formed by minute, fluid-filled tunnels that permit passage of electrical signals or chemicals (i.e., ions and small molecules) from 1 cell to a neighboring cell?
gap junction
where are gap junctions located in?
in some parts of nervous system, heart muscles, and in gastrointestinal tract
what are some of the functions of epithelial tissue or epithelium?
protection filtration secretion absorption excretion
which tissue has avascular tissue that exchanges materials with adjacent connective tissue via diffusion?
epithelial tissue
which tissue has a nerve supply?
epithelial tissue
which tissue cells have lateral surfaces, apical (free) surface and basal surface?
epithelial tissue
what are the 2 major types of epithelial tissue?
- covering and lining epithelium
2. glandular epithelium
what are the arrangements of covering and lining epithelium tissue?
- simple (unilaminar) epithelium (single layer of cells)
- pseudostratified epithelium (single layer that appears stratified)
- stratified (multilaminar) epithelium (2 or more layers of cells)
what are the cells shapes of epithelial tissue?
- squamous (flattened cell)
- cuboidal (cube or hexagons)
- columnar (tall & cylindrical)
- transitional (cells able to undergo changes in shape caused by distention)
epithelium are classified by what characteristics?
according to NUMBER OF LAYERS present, and CELL SHAPES (in apical layer)
SIMPLE SQUAMOUS EPITHELIUM
- located in areas subject to little wear and tear
- adapted for DIFFUSION (ex. lung alveoli) and FILTRATION (ex. blood filtration in kidneys)
SIMPLE CUBOIDAL EPITHELIUM
SECRETION & ABSORPTION (ex. lines kidney tubules and smaller ducts to many glands
SIMPLE COLUMNAR EPITHELIUM
some have cilla (ex. upper respiratory passageways) and some have microvilli (to increase efficiency of absorption
PSEUDOSTRATIFIED COLUMNAR EPITHELIUM
functions in secretion of movt of materials by ciliary action (upper respiratory passageways)
STRATIFIED SQUAMOUS EPITHELIUM
provides protection in areas subject to wear and tear (ex. outer layer of skin, lining of mouth)
STRATIFIED CUBOIDAL EPITHELIUM
(rare type) provides protection (ex. ducts of adult sweat glands)
STRATIFIED COLUMNAR EPITHELIUM
(rare type)
protection and secretion (ex. large ducts of some glands)
TRANSITIONAL EPITHELIUM
contains cells that may undergo changes in shape and therefore is located in areas subject to stretching (ex. UB)
what are specialized epithelial cells organized to from GLANDS that SECRETE substance into ducts, onto a surface, or into blood?
glandular epithelium
which glands are ductless and secrete hormones which diffuse through the interstitial fluid into the blood?
what are examples of this gland?
endocrine glands
ex. thyroid gland, adrenal glands
which glands secrete substances into DUCTS and are structurally classified into UNICELLULAR and MULTICELLULAR GLANDS?
exocrine glands
what are examples of exocrine glands?
sweat and salivary glands
which glands are functionally classified into MEROCRINE or ECCRINE (ex. salivary), APOCRINE (mammary), and HOLOCRINE (sebaceous) glands?
exocrine glands
