A&P- cytology

Cells are responsible for what?

ALL structural and functional properties of a living organism

What are the different cell shapes?

1. squamous

thin, flat and scaly

2. cuboidal

square-looking

3. columnar

taller than wide

4. polygonal

irregular shape

5. stellate

star-shaped cells

6. spheroid

ball-like shape

7. discoidal

disc-like

8. fusiform

eye-shape w/ tapered ends

9. fibrous

elongated and long

What gives the cell its shape?

the cytoskeleton

What are the three main components of cell?

1. plasma membrane

2. cytoplasm

3. extracellular fluid (ECF)

What are the three functions of the plasma membrane?

1. defines cell boundaries

2. governs interactions with cell

3. controls passage of materials

What is the plasma membrane composed of?

membrane lipids (75% phospholipids and 20% cholesterol) and membrane proteins

The Glycocalyx

fuzzy coat external to plasma membrane consisting of glycoproteins or glycolipids

What are the functions of the glycocalyx?

1. protection

2. cell adhesion

3. immunity to infection + foreign cells

4. fertilization

5. defense against cancer

6. embryonic development

7. transplant compatibility

What are the different cell surface extension types and functions?

1. microvilli

2. cilia

3. flagella

4. pseudopods

Microvilli

finger like extensions formed on epical surface

function: increases surface area and allows for absorption

ex. located in digestive system

Cilia

hair-like processes on epical surface that beats in waves

function: serves to protect and helps with movement

ex. located in respiratory tract

Flagella

tail of sperm that has whip-like structure

function: facilitates movement

Pseudopods

continually changing extensions of the cell that vary in size and shape

function: cellular locomotion and engulfing foreign particles

What are the three membrane transport mechanisms?

1. passive mechanism

2. active mechanism

3. carrier-mediated mechanism

Filtration

(passive)

particles dissolved in fluid are driven through membrane by physical pressure

ex. allows delivery of water and nutrients to tissues through capillary walls

Simple diffusion

(passive)

the net movement of particles from high to low concentration without requiring a membrane

ex. movement of oxygen

Osmosis

the net flow of water through a selectively permeable membrane where water moves from more concentrated to less concentrated

Tonicity

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

Hypotonic solution

this solution has a lower concentration of solutes than intracellular fluid

ex. causes cell to absorb water and swell

Hypertonic solution

this solution has a higher concentration of solutes than intracellular fluid

ex. causes cell to lose water and shrivel (crenates)

Isotonic solution

the concentration of solutes is same both inside and outside of cell

ex. causes no change in cell volume

What are the different types of carrier-mediated facilitated diffusion?

1. primary active transport

2. secondary active transport

3. facilitated diffusion

Vesicular transport

moves large particles or numerous molecules through a membrane in vesicles by utilizing ATP (energy)

What are the different types of vesicle transport?

1. endocytosis

brings material into cell

two types: phagocytosis (cell eating) pinocytosis (cell drinking)

2. exocytosis

secretes material from cell

3. transcytosis

includes both endo and exo cytosis

What are the different membrane proteins and their functions?

1. receptors

2. enzyme

3. channel

4. gated channel

5. cell-identify marker

6. cell-adhesion marker

What is the cytoskeleton composed of?

microfilaments, intermediate fibers, and microtubules

Organelles

internal structures of a cell that carry out specialized metabolic tasks

ex. both membranous and nonmembranous

The nucleus and its components

largest organelle

composed of the nucleoplasm, chromatin (DNA and protein), and nucleoli (where ribosomes are produced)

Nuclear envelope

double membrane that surrounds the nucleus

Endoplasmic Reticulum

system of channels (cisterns) enclosed by a membrane

ex. two types

Rough Endoplasmic Reticulum

parallel flattened sacs covered with ribosomes and continuous with outer membrane of nuclear envelope

ex. produces phospholipids and proteins

Smooth Endoplasmic Reticulum

branching cisterns continuous with rough ER that lack ribosomes

ex. serves for synthesize steroids and lipids, detoxification, and calcium storage

Ribosomes

small masses of protein and RNA

ex. synthesize proteins

Where are ribosomes located?

nucleus, rough endoplasmic reticulum, and free in cytoplasm

Golgi complex

a system of cisterns with sac-like structures that receive and modify proteins sent from the endoplasmic reticulum

sorts proteins, adds carbohydrates to some, and packages them into membrane bound Golgi vesicles

ex. also synthesizes carbs

Lysosomes

packages of enzymes that serves for intracellular digestion of substances

Autophagy

digestion of a cell’s surplus organelles

Autolysis

digestion of the cell itself

ex. “cell suicide”

Peroxisomes

resemble lysosomes

uses oxygen to oxidize organic molecules and detoxify alcohol, drugs, and blood borne toxins

ex. abundant in liver and kidneys

Proteasomes

cylindrical organelle that disposes of excess proteins

ex. contains enzymes

Mitochondria

double membraned organelle specialized for synthesizing ATP

contains folds called “cristae”

ex. termed “powerhouse of cell”

Centrioles

a short assembly of microtubules that plays a role in cell division

Inclusions

stores both cellular products and foreign bodies

ex. not essential for cell survival

What are the two main phases of the cell cycle?

mitotic phase and interphase

Interphase

1. G₁ phase

when cell accumulates materials

2. S phase

cell replicates DNA and centrioles

3. G₂ phase

cell finalizes materials for cell division

Mitotic phase

1. prophase

materials condense into thick chromosomes (46) with two chromatids each

nuclear envelope disintegrates

2. metaphase

chromosomes align on cell equator and attach to centrioles

organelles divide into two sets

3. anaphase

enzymes cleave chromosomes apart as they migrate to opposite poles

4. telophase

nuclear envelope appears on each cell

each nucleus forms nucleoli

Cytokinesis

overlaps with telophase

division of the cytoplasm into two separate cells

Mitosis

cell division resulting in two genetically identical daughter cells

purposes:

• development of individual from fertilized egg to about 50 trillion cells

• growth of all tissues and organs after birth

• replacement of cells that die

• repair of damaged tissues

What is the intracellular fluid of a cell?

the cytosol (ICF)

What is the extracellular fluid of a cell?

the fluid outside of cells (ECF) including tissue (interstitial fluid)

Interstitial fluid

fluid outside the cell, surrounding it