Health Occupations

The Cell

Definitions

AnatomyStudy of form & structure of organism

PhysiologyStudy of processes of living organisms, why & how they work

Pathophysiology Study of how disease occurs & responses of living organisms to disease processes

Protoplasm

Basic substance of life Makes up all living things Carbon, oxygen, hydrogen, sulfur,

nitrogen, phosphorus Unique combo we call life Forms the basic unit of structure in all

living things – the cell

The Cell Microscopic Carries on all functions of life Building block of the body Functions

– Takes in food and oxygen– Produces heat & energy– Moves & adapts to the environment– Eliminates wastes– Performs special functions– Reproduces to create new, identical cells

Cell Parts

Cell Membrane –– Outer protective covering– Semi permeable

• Allows certain substances in & out• Prevents other substances from leaving or

entering

Cell Membrane

Cell Parts

Cytoplasm– Jelly like fluid inside cell that surrounds cell parts– Water, proteins, lipids, CHO, minerals, salts– Site for all chemical reactions in cell– Contains organelles

• Cell structures that help cell function• nucleus, mitochrondria, ribosomes, liposomes,

centrioles, Golgi apparatus, endoplasmic reticulum

Cell MembraneCytoplasm

Cell Parts - Organelles

Nucleus– Brains of the cell– Controls cell activities– Directs reproduction

Cell MembraneCytoplasm

Nucleus

Cell Parts - Organelles

Nucleolus– Inside nucleus– Important for reproduction– Manufactures ribosomes

• RNA – ribonucleic acid & protein• Move from nucleus to cytoplams• Aids in protein synthesis (production)• Can exist freely or as attached to endoplasmic

reticulum

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Cell Parts - Organelles Chromatin

– Inside nucleus– Make up of DNA

• Deoxynucleic acid & protein

– During reproduction• Chromatin condenses & forms chromosomes• Human has 46 or 23 pairs• Chromosomes

– 100,000 genes with inherited characteristics– Gene

» Specific & unique code of about 1,000 DNA pairs that carry coding for exact cell duplication

» Can be used for identification because each sequence is unique

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Cell Parts - Organelles

Centrosome– Located in cytoplasm near nucleus– Contains 2 centrioles– During mitosis (cell division), centrioles

separate– Cytoplasmic spindle fibers form between

centrioles & attach to chromosomes• Creates an even division of chromosomes in

the 2 new cells

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Cell Parts – Organelles

Mitochondria– Rod-shaped– Furnaces or power houses of cells– Break down CHO, proteins, fats– Produce ATP

• Adenosine triphosphate• Cell’s major energy source

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Cell Parts - Organelles

Golgi Apparatus– Stack of membrane layers– Produces, stores, packages secretions for

discharge from cell– Salivary, gastric, pancreatic cells have

many golgi apparatus

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Golgi apparatus

Cell Parts - Organelles

Endoplasmic reticulum (ER)– Fine network of tubular structures– Allows for transport of materials in & out of

nucleus– Aids in synthesis & storage of proteins– Rough Endoplasmic reticulum

• Has ribosomes, sites for protein production

– Smooth Endoplasmic reticulum• No ribosomes, not present in every cell• Assists with cholesterol synthesis, fat metabolism, &

drug detoxification

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Golgi apparatus

Rough ER Smooth ER

Cell Parts - Organelles

Lysosomes– Oval or round bodies in cytoplasm– Contain digestive enzymes that digest and

destroy• Old cells• Bacteria• Foreign materials

– Important function of immune system

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Golgi apparatus

Rough ER Smooth ERLysosome

Cell Parts – Organelles

Pinocytic vessels– Pocket like folds in cell membrane– Allow large molecules like fats & proteins to

enter cell– When molecules are inside, folds close to

form vacuoles or bubbles in cytoplasm

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Golgi apparatus

Rough ER Smooth ERLysosome

Pinocytic vessel

Cell Parts - Organelles

Vacuole– Closet or storage place of cell– May be empty or full– Looks like bubble in cytoplasm

Cell MembraneCytoplasm

Nucleus

NucleolusRibosomes

Chromatin

Centrosome

Mitochondria

Golgi apparatus

Rough ER Smooth ERLysosome

Pinocytic vessel

Vacuole

Homeostasis

Tendency of a cell to maintain a state of balance

Molecules pass in & out of cell to do this Cells constantly adjust these to maintain

balance– Fluids– Temperature– Oxygen– Electrolytes– Nutrients

Electrolytes

Compounds made of charged particles or ions Conduct electrical current in water or

cytoplasm + charge = cation (acid) Na++, K+, Mg++, H+ - charge = anion (base) HCO3, HPO4, C, SO4) pH measures how much acid/base is present

– Each tissue has own normal pH– If pH is not maintained, cell doesn’t function right

Cellular reproduction

Mitosis – Most cells– Divides into 2 identical cells– Asexual– Continuous reproduction

• Skin, blood, intestines

– Every few years• Muscle

– Never• Spinal cord, nervous cells, brain cells

Mitosis

1. DNA molecules duplicate themselve2. Centrioles separate & a spindle forms

between them3. Duplicated chromosomes line up along

center of spindle4. Chromosomes separate5. Two nuclei form as cell separates6. Each new cell has the full number of

chromosomes

Meiosis

Process by which sex cells divide Uses 2 separate cell divisions to

produce 4 new cells Ova – female cells Spermatozoa – male cells Chromosome number decreases to 23

(1/2 of mitosis) before division

Meiosis

When ova & sperm join, form a zygote (new cell) with 46 chromosomes (23 from ova & 23 from sperm)

After zygote forms, rapid mitosis occurs 4-5 days, becomes blastocyst which contains

embryonic stem cells– Stem cells have ability to transform into any

specialized cell & perform functions– Controversy – can stem cells cure diseases like DM,

Parkinson’s disease, osteoporosis, arthritis, heart disease?

Heredity Passing on of genetic information that determines

individual characteristics Determines physical appearance, blood type, gender Genes

– Contain heredity info in cell– Made up of DNA forming chromosomes– 50-100,000 genes on each chromosome determining

general human & individual traits– Dominant gene – characteristic appears when only 1 gene

is inherited– Recessive gene – trait only appears when gene is present

on both chromosomes

Abnormal genes Cause many inherited, hereditary, or genetic

disorders Described as CONGENITAL or CONDITION

rather than contagious or disease Some disorders affect only 1 body part, others

affect entire systems Disorders include – clubfoot, cleft lip/palate, cystic

fibrosis, Down’s syndrome, Huntington’s chorea, Klinefelter’s syndrome, Neural tube defect, Neurofibromatosis, PKU, Sickle cell anemia, Tay-Sachs disease