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Cellular form and function
Anatomy & Physiology 1 cellular form and function
55
Physiology
Undergraduate 1
07/07/2012

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Cards

Term
Theodor Shwann
Definition

Studied a wide range of animal tissues and concluded that all animals are made of cells.

 

 

Term
Louis Pasteur
Definition
French microbiologist who discredited the idea of spontaneous generation
Term
Modern cell theory
Definition

All organisms are composed of cells

Cell is the simplest structural and functional unit of life

Cells come from preexisting cells

All life traces its ancestry to the same original cells

Cells of all species are similar

Term
Squamous Cell
Definition

A thin, flat, scaly shape, often with a bulge where the nucleus is.

Looks like a sunny side up egg

Lines the esophagus

Forms the surface layer of the skin (epidermis)

Term
Cuboidal cells
Definition

Squarish around the front and similar in height & width.

Found in liver & muscle cells

Term
Columnar cells
Definition

Taller than wide

Found in the inner lining of the stomach and intestines

Term
Polygonal Cells
Definition
Irregularly angular shape with four or five or more sides
Term
Stellate cells
Definition

Multiple pointed processes, giving it a starlike shape.

Found in nerve cells

Term
Spheroidal Cells
Definition

round or oval

Found in egg cells and white blood cells

Term
Discoid cells
Definition

Disk shaped

Found in red blood cells

Term
Fusiform Cell
Definition

Spindle shaped

Long with a thick middle and tapered ends

Found in smooth muscle cells

Term
Fibrous
Definition

Long, slender, threadlike

Found in skeletal muscle cells & the axons of nerve cells

Term
Cell Size
Definition

Human Cells are 10-15 micrometers

egg cells are large and measure 100 micrometers

nerve cell is long and measures 1 meter

If a cell becomes too large, it may have too little plasma membrane to serve the metabolic needs of its increased volume of cytoplasm.

It cannot support itself and is at risk of rupturing like an overfiller water balloon

When a cell is growing, its volume increases faster than the surface area

Nutrient absoption uses surface area

Volume increses 8X

Surface increases 4X

Term
Plasma membrane
Definition

Surrounds the cell

Controls the passage of materials in and out of cell

It is made of an oily film of 98% lipids with 2% proteins embedded in it

 

 

Term
Cytoplasm
Definition
Contains the cytoskeleton, organelles & cytosol
Term
Cytoskeleton
Definition

A supportive framework of protein filaments and tubules. Provides a specific shape for organelles

help hold epithelial cells together

determines shape of cell, provides support, orgqanization & movement

Term
Organelles
Definition

Diverse structures that perform various specialized metabolic tasks for the cell

membranous organelles are: nucleus, mitochondria, lysosome, peroxisome, ER & Golgi complex

no membrane: ribosome, centrosome, centriole, basal bodies

 

 

Term
Cytosol
Definition
Intracellular Fluid. Clear gel surrounding the cytoskeleton
Term
Membrane Lipids
Definition

75 % of the lipids are phospholipids, with hydrophobic tails directed towards the center avoiding the water, and hydrophilic heads facing the water on each side of the membrane.

20% of lipids are cholesterol molecules, which holds phospholipids still & makes the membrane less fluid in spots. Too much cholesterol can increase membrane fluidity preventing phospholipids from becoming packed closely together.

5% of membrane lipids are glycolipids found on the extracellular face of the membrane. Help form glycocalyx.

Term
Membrane Proteins
Definition

2% of the membrane are proteins. However, they are larger than lipids and constitute about 50% of the membrane weight.

The 2 classes of membrane proteins are Transmembrane & Peripheral.

Term
Transmembrane proteins
Definition

Also called integral proteins.

Have hydrophilic regions and penetrate the phospholid bilayer and sometimes all the way through the membrane

Are mostly glycoproteins

Some are anchored to the cytoskeleton

Term
Peripheral Proteins
Definition

Do not protrude into the phospholipid layer, but adhere to one face of the membrane.

Typically anchored to a transmembrane protein as well as to the cytoskeleton

Term
Receptors
Definition

Surface proteins of the cell that receive chemical signals that cannot penetrate the cell.

Specific for one particular messenger.

They can bind chemicals and transport them into the cell.

Term
Enzymes
Definition

Carry out final stages ofch and protein difestion in the small intestine.

Break down hormones and other signaling molecules whose job is done, thus stopping them from excessively stimulating a cell.

Term
Channel(gates)
Definition

Allow water and hydrophilic solutes to move through the membrane.

Can be tunneled through through an individual protein or surrounded by a comple of multiple proteins.

Some are always open, whereas others are gates that open and close under different circumstances.

Term
Cell identity markers
Definition
Functions like an identification tag that enables our bodies to tell which cells belong to it and which are foreign invaders
Term
Cell adhesion molecules (CAMs)
Definition
Act as as glue for cells in order for them to adhere to one another and to extracellular material.
Term
Glycocalyx
Definition

Fuzzy coat

composed of carbs moieties

Chemically unique

sushions the plasma membrane & protects it from chemical and physical injury

enables immune system to recognize & attack foreign organisms

basis of blood transusions, tissue grafts & organ transplant

Cells adhesion in order for tissues not to fall apart

enables sperm to recognize & bind to eggs

guides embryonic cells to their destination

 

Term
Microvilli
Definition
extensions of the membrane that increase a cell's surface area for absorption (brush border)
Term
Cilia
Definition

hair like processes

nearly every cell in the inner ear, retina & nasal cavity has a nonmotile cilium that serve as sensories

They exist within a saline layer

motile cilias move substances across their surface in a wavelike motion always in the same direction (respiratory system)

Term
Flagella
Definition
whiplike tail of a sperm
Term
Cystic Fibrosis
Definition

hereditary disease primarily affecting white europeans

cells make chloride pumps but fail to install them in the membrane causing little to no saline layer under mucus, so it becomes dehydrated and overly sticky

thick mucus clogs pancreatic ducts & respiratory tract

inadequate absorption of nutrients & oxygen

lung infections

life expectancy of 30 years

Term
Membrane Transport
Definition

selectively permeable-allows some things though, such as nutrients and wastes, but usually prevents other things like proteins and phosphates from entering or leaving cell

Passive & active transports are the 2 methods that is used to move substances

Term
Passive Transport
Definition

requires no energy to move down concentration gradient

includes filtration, difussion & osmosis

 

Term
Active Transport
Definition

requires energy (ATP)

carrier mediated mechanisms use a membrane protein to transport substances

vesicular transport

facilitated diffusion

Term
Osmosis
Definition

Diffusion of water through a SPM from areas of more water to areas of less water

accumulates in the side of higher solute (less water)

osmotic pressure- amount of pressure to be applied to one side of a membrane to stop osmosis

osmolarity is the # of osmoles / liter os solution

physiologica solutions-measured in milliosmoles per litter mOsm/L 10 to the -3

osmolarity of bloos plasma is 300 mOsm/L

Term
Hypotonic
Definition

lower concentration of solutes with higher concentration of water than inside cells

a cell in this solution will absorb water, swell and may burst. <- cannot be reversed

Term
Hypertonic
Definition

higher concentration of solutes with lower concentration of water than inside cells

cells lose water, shrivel (crenate) <-can be reversed

cells may die from torn membranes & cytoplasmic loss

Term
Isotonic
Definition

normal saline, same concentration of suolutes and water than the ICF

has no effect on fluid volume and pressure

Term
Nucleus
Definition

largest organelle

genetic control center of cell that has the information to make proteins-> stored in the chromosones, stored in the dark masses in the nuceoli, which are made of DNA

has 2 membranes

 

Term
Lysosomes
Definition

digestions of large molecules such as: worn out organelles (autophagy) and cells programmed to die (autolysis)

breakdown of stored glycogen in liver

Term
Mitochondrion
Definition

double membrane

powerhouse of the cell- converts chemical energy stored in food into energy stored in ATP

only maternal mitochondria is inherited, sperm mitochrondria usually is destroyed inside egg

Term
Peroxisomes
Definition

resemble lysosomes but contain different enzymes & tocix radicals

neutralize free radicals

detoxify alcohol. drugs, & toxins

breakdown fatty acids

Term
Rough Endoplasmic Reticulum
Definition

membranous sacs covered in ribosomes

continues with nuclear envelope & sER

synthesis and modification of proteins happens here

Term
Smooth Endoplasmic Reticulum
Definition

lacks ribosomes

synthesis of lipids, membranes, steroids happens here

detoxification of the liver and kidney

calcium storage in the skeletal and cardiac muscle

Term
Ribosomes
Definition

granules of protein and RNA (assembled in the nucleus)

attaches to the rER & roams free in cytosol

make proteins using the soecified DNA, follow directions coded in mRNA to assemble amino acids into proteins

Term
Golgi Complex
Definition

system of flattened sacs (cisternae)

packages & delivers proteins & glycoproteins

synthesizes carbs

forms vesicles

Term
Centrioles
Definition

form the centrosome

two perpendicular centriolis near nucleus, made of short cylindrical microtubules

has a role in cell division and cilia formation

Term
Filtration
Definition

part of passive transport

physical pressure forces fluid through a selectively permeable membrane -hydrostatic pressure (water force)

filtrates nutrients from blood into tissue fluids

filtrates wastes from blood into the kidneys

 

 

Term
simple diffusion
Definition

movement of particles from areas of high concentration to low concentration down the concentration gradient

it does not need a membrane

it is not selective

Factors that affect the rate of diffusion through a membrane are:

temperature- the warmer a substance, the faster the particles diffuse

molecular weight- larger molecules move slower

membrane surface area- more particles diffuse with a bigger surface

membrane permeability- depends on how permeable it is to the particles.

Term
Tonicity
Definition

ability of a solution to affect the fluid volume and pressure in a cell

 

Term
Carrier mediated transport
Definition

carries solutes across cell membran by binding to a receptor, changes shape and releases the solute to the other side of the membrane

Can move substances in and out of the cell, or in and out of organelles

Facilitated diffusion- no energy used:-glucose is transported across membrane down its concentration gradient by changing confirmation and releasing solute to other side of the membrane

active transport- moves up the concentration gradient, uses ATP

 

 

Term
Membrane carriers
Definition

uniporter- carries only one solute at a time

symporter-carries 2 or more solutes simultaneously in same direction(cotransport)

antiporter-carries 2 or more solutes in opposite directions (countertransport)

any of the carriers can use facilitated diffusion or active transport

Term
vesicular transport
Definition

moves large particles or fluid droplets in vesicles at the same time

endocytosis- brings matter into a cell

exocytosis- releases material from a cell

these processes employ motor proteins whose movements are energized by ATP

 

Term
endocytosis forms
Definition

phagocystosis- "cell eating" engulfs large particles

pinocytosis- "cell drinking" takes in fluid droplets that are useful to the cell

receptor mediated endocytosis-takes in specific molecules with minimum unnecessary matter.

transcytosis-captures molecules in one side and release on the other side where tissue cells await.

 

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