Anatomy Cells Textbook

Cytology

study of cellular structure and function

Who helped start cytology

Robert Hooke and Antony van Leeuwenhoek

what are major components of cells

Plasma membrane
Cytoplasm
Cytoskeleton
Organelles
Inclusions
Cytosol

Plasma Membrane (cell membrane)

The membrane that encloses a cell and controls the traffic of molecules into and out of the cell.

what is the largest organelle

nucleus

Cytoplasm

The contents of a cell between its plasma membrane and its nuclear envelope

the cytoplasm consists of

cytosol, organelles, inclusions, and the cytoskeleton

cytoskeleton

a supportive framework of protein filaments and tubules

organelles

diverse structures that perform various metabolic tasks for the cell

inclusions

accumulated cell products such as lipids and pigments or internalized foreign matter such as dust and bacteria

cytosol

A clear, featureless, gelatinous colloid in which the organelles and other internal structures of a cell are embedded.

cytosol is also called

intracellular fluid (ICF)

intracellular fluid (ICF)

The fluid contained in the cells; one of the major fluid compartments.

Extracellular (ECF)

Any body fluid that is not contained in the cells;

where are some locations where ECF is located

blood, lymph, and tissue fluid

ECF is located between the cells is also called

tissue fluid

what is the most useful unit of measurement for designating cell sizes

micrometer (um)

How wide are most human cells

10 to 15 um

what are the longest human cells and how long

nerve cells
meter long

muscle cells
30 cm long

cells cannot attain ____ size

unlimited

What will happen when a cell grows to big

too large it would rupture; could not diffuse from place to place fast enough to support its metabolism

what is an advantage of having many small cells instead of a few large ones

death of one or a few cells is of less consequence to the structure and function of the whole organ

what are examples of physiology takes place at the cell surface

binding of signal molecules such as hormones, the stimulation of cellular activity, the attachment of cells to each other, and the transport of materials into and out of cells

plasma membrane defines the ____ of a cell and governs its ____ with ____ ___

boundary
interactions with other cells

plasma membrane also controls and maintains

the passage of materials into and out of the cell and maintains differences in chemical composition between the ECF and ICF

the term plasma membrane refers to

exclusively to the cell surface

description of plasma membrane

oily, two-layered lipid film with proteins embedded in it

how much of lipid molecules are phospholipids

75%

phospholipids

composes most of the molecules of the plasma membrane and other cellular membranes.

phospholipids are

amphipathic

phospholipids have a ____ phosphate head and two _____ fatty acid tails

hydrophilic
hydrophobic

phospholipids are not ___ but ___

stationary but highly fluid

How much of lipid molecules is cholesterol

20%

cholesterol

A steroid that functions as part of the plasma membrane and as a precursor for all other steroids in the body.

cholesterol affects

membrane fluidity

What happens is too much cholesterol

inhibits the action of enzymes and other proteins in the membrane

what happens is too little cholesterol

plasma membranes become excessively fragile

How much of lipids is glycolipids

5%

glycolipids

A phospholipid molecule with a carbohydrate covalently bonded to it, found in the plasma membranes of cells.

Proteins give membranes

specific abilities

Protein contribute greatly

to the functional differences between cell types

peripheral proteins

proteins that only adhere to the inner surface of the plasma membrane

Integral proteins

protein that penetrates all the way through

glycoproteins

A protein molecule with a smaller carbohydrate covalently bonded to it

channel protein

A protein in the plasma membrane that has a pore through it for the passage of materials between the cytoplasm and extracellular fluid

channel proteins act as ____ that ___

gates that open or close to allow material to pass through only at specific times

Gates are important for

timing of heart's pacemaker, conduction of nerve signals, and contraction of muscles

Other functions of proteins

actively bind to chemicals in the ECF or ICF, such as glucose, amino acids, and inorganic ions, and transport them through the membrane

act as receptors for hormones and other chemical messengers from other cells

enzymes that carry out chemical rxns at the cell surface

Receptor function

a receptor that binds to chemical messengers such as hormones sent by other cells

Enzyme function

an enzyme that breaks down a chemical messenger and terminates its effect

Channel function

a channel protein that is constantly open and allows solutes to pass into and out of the cell

Gated channel function

a gate that opens and closes to allow solutes through only at certain times

cell-identity marker function

a glycoprotein acting as a cell identity marker distinguishing the body's own cells from foreign cells

cell-adhesion molecule (CAM) function

a cell-adhesion molecule (CAM) that binds one cell to another

All cells are covered with a fuzzy carbohydrate coat called the

glycocalyx

gyclocalyx

A layer of carbohydrate molecules covalently bonded to the phospholipids and proteins of a plasma membrane; forms a surface coat on all human cells.

Glycocalyx functions

cell-adhesion molecules that bind cells together and precent tissues from falling apart

cushions that plasma membrane and protects it form physical and chemical injury

Glycocalyx are chemically ___ and act like an ___ ___

unique

identification tags

What is determined by the glycocalyx

human blood types and transfusion compatibility

List surface extensions of cells

microvilli
cilia
flagella
pseudopods

what do surface extensions do for cells

aid in absorption, movement, sensory processes, and phagocytosis

microvilli

extensions of the plasma membrane that serve primarily to increase its surface area

what cells are best for microvilli

cells specialized for absorption such as epithelial cells of the small intestine and kidney tubules

How much more surface area can microvilli give a cell

40 times more absorptive surface area

cilia

hair like process that are supported by a core of microtubules

What are microtubules equipped with and what does it do

little motor proteins that produce the beating motion of cilium

How many cilia do the respiratory tract and uterine (fallopian) tubes typically have

50 to 200

What does cilia do in the respiratory tract

moves mucus from the lungs and trachea up to the throat where it is swallowed

what does cilia do in the uterine tubes

move an egg or embryo toward the uterus

primary cilium

nonmotile, solitary cilia in which nearly every cell has

primary cilium function

Serves as antenna for monitoring nearby conditions
play roles in the senses of motion and balance; in the retina of the eye. form light-absorbing part of sensory cells, and in kidney tubules the monitor fluid flow

flagellum

resembles a long solitary cilium

what is the only functional flagellum in humans

whiplike tail of a sperm cell

Kartagener syndrome

a hereditary disease in which cilia and flagella lack the motor protein and therefore cannot move

pseudopods

A temporary cytoplasmic extension of a cell used for locomotion (ameboid movement) and phagocytosis

pseudopods can change

shape continually

what uses pseudopods and for what

white blood cells- use pseudopods to crawl about in the tissues, and when they encounter a bacterium or other foreign particles

Macrophages-snare bacteria with thin filamentous pseudopods and reel them in to be digested by the cell

macrophages and white blood cells keep

our tissues cleaned up and defend us against bacteria and other invaders

cellular junctions

cells linked to one another and to the extracellular environment

cellular junctions enable cells to

grow and divide normally, resist stress, and communicate with each other

Three principal types of connections

tight junctions
desmosomes
gap junctions

tight junction

completely encircles an epithelial cell near its upper end and joins it securely to adjacent cells

Tight junctions are formed by

the fusion of the plasma membrane of neighboring cells, and seal off the intercellular space

in a tight junction substances are restricted

from passing between the epithelial cells, but rather must pass through them, ensuring that the epithelial cells chemically process materials that travel across

desmosome

A patchlike intercellular junction that mechanically links two cells together

desmosome keep cells

from pulling apart and thus enable a tissue to resist mechanical stress

Desmosomes are common

in tissues as the epidermis and cardiac muscle

gab junction

A junction between two cells consisting of a pore surrounded by a ring of proteins in the plasma membrane of each cell

gap junction function

allows solutes to diffuse from the cytoplasm of one cell to the next, thereby serving for cell-to-cell electrical and chemical communication in tissues such as cardiac and smooth muscle

Cellular membranes list

epithelia
plasma membranes
intracellular membranes

epithelia

(sheet of cells) that line the blood vessels, digestive and respiratory tracts, and other surfaces

plasma membranes

form the outer boundaries of all cells

intracellular membranes

various organelles

membranes cannot be ____ but must allow _______

impenetrable
chemicals to pass through

these membranes are all ___ ___, allowing some substances to pass through while excluding others

selectively permeable

pemphigus vulgaris

desmosomes are destroyed
launches a misguided attack on the desmosome proteins, especially in the skin

filtration

A process in which hydrostatic pressure forces a fluid through a selectively permeable membrane (especially a capillary wall).

The most important example of filtration in human body

blood pressure driving water and small solutes through gaps in the walls of the capillaries, while holding blood cells and large molecules such as proteins in the bloodstream

Filtration is the mechanism by which

salts, nutrients, and other blood solutes are delivered to the cells of surrounding tissues, and how the kidneys selectively filter wastes from the blood

simple diffusion

the net movement of particles from a place of high concentration to a place of low concentration (down a concentration gradient)