Chemistry, Cells and Tissues

By Mary Beth Vogel, BSN, RN-C

Useless facts:* All the chemicals in a human body combined are estimated to be

worth

less than $10

* The average human body contains enough: iron to make a 3 inch nail, sulfur to kill all fleas on an average dog, carbon to make 900 pencils, potassium to fire a toy cannon, fat to make 7 bars of soap, phosphorous to make 2,200 match heads, and water to fill a ten-gallon tank.

Chemistry Review…

4 kinds of atoms make up 96% of the human body: O2, C, H, N

Chemical Makeup of the Body 1. Water

2. Oxygen

3. Carbon Dioxide

4. Carbohydrates

5. Lipids

6. Proteins

7. Nucleic Acids: DNA and RNA

Major Types of Organic Compunds

CARBOHYDRATESMono, di, and polysaccharidesLIPIDSTriglycerides, chol., phospholipidsPROTEINFibers, enzymes, amino acidsNUCLEIC ACIDDNA, RNA

(FUNCTION)Source of energy

Stores energy, forms cell membranes

Forms structures, sends signals & reaxs

Genetic code for making proteins

8. Acids and Bases: H balanced by OH

pH scale: H+ and OH- ions balanced at 7

Basic: pH >7; low H/high OH

Acidic: pH <7; high H/low OH

Cells and Tissues

Diversity of Cells in the Human Body

Cell Functions Absorption

Metabolism

Release energy

Synthesize proteins

Excrete waste

Reproduce itself

Support functions specific to that cell

Cellular Fluids Dilute watery solutions found inside and outside cells

Contain O2, nutrients, proteins, ions

ICF: inside cells (cytosol)

ECF: outside cells (interstitial fluid)

Plasma: ECF in bld vess

Lymph: ECF in lymph vess

CSF: ECF @ brain, spinal cord

Components of Cytoplasm (“living matter” inside cells) H2O

Ions

Proteins

Nutrients

Lipids

Organelles

Plasma Membrane

Outer bi-layer

Selectively permeable

Phospholipids form this fluid framework of the plasma membrane

Contain receptors

Identifies cells as its own

Functions:

Physical isolation

Regulation of exchange w/ env

Sensitivity

Structural support

Cell Division

Mitosis: cell division: 1 cell forms 2 identical cells w/ same # chromosomes

Diploid/somatic cells undergo mitosis

Meiosis: cell division – ½ the # of chromosomes contributed by each

Haploid cells prod gametes

Mitotic rate

Mitotic rate: rate of cell div Generally: longer cell life expectancy = slower the

mitotic rate Stem cells undergo frequent mitosis

Changes in Cell Growth: Hypertrophy Atrophy

Mitosis and CA

Neoplasm Benign vs malignant Differentiation Hyperplasia Dysplasia Anaplasia

More on CA 2nd leading cause of death in US 1.5 million dx w/ CA in 2005 (ACS) Nearly 1/2 of all men and 1/3 of all women in the

US will develop CA at some point in their lives Skin CA (non-melanoma) is the most common form

of CA in US

Development of CA linked to 3 factors: aging, genetics, environment

Environmental exposures: tobacco, etoh, diet, lack of ex, sunlight, chemicals, hormones, infections

Less to do with exposure/env and more

to do with the increased

longevity?

Breast cancer cell

TX: surgery, radiation and/or chemotherapy are primary tx

Transport Mechanisms

Mvmnt of substances in/out of cell

Active vs Passive

1. Passive Transport

No additional energy required; down a press gradient

Types:

1. Diffusion (osmosis and dialysis)

2. Filtration

DiffusionVariations:

a. Osmosis: Diffusion of H2O (all cells)

B. Dialysis: Diffusion of solutes

Filtration: movement of water & solutes as result of hydrostatic pressure

2. Active transport

Uphill mvmt (move from lower concentration to higher)

Requires ATP (energy)

Several types:

Ion Pumps

Phagocytosis

Pinocystosis

ION PUMP

Active transport in the cell membranes Mvmvnt of ions against concentration gradient The “pump” is a prot complex Ion specific or can be coupled

Na pumps, Ca pumps, K pumps, Na/K pumps

Na-K Ion Pump

a. Phagocytosis: intake of solids

b. Pinocytosis: intake of fluids

Tissues

Group of cells w/ similar struc/funct

Differ from each other based on:

Size/shape of cells

Matrix

Function

Types Tissues

The four tissue types are: Epithelial Connective Muscular Nervous

1. Epithelial Tissue

Covers the body, lines

various structures

Protective

Cells packed tightly

Classified by

shape/arrangement

of cells

Location of Epi Tissues

Simple Squam: alveoli, capillaries Stratified Squam: skin, esophagus Simple cuboidal: glands, kidney Stratified cuboidal: rare; some ducts Simple columnar: lining of stomach/int , resp tract Stratified columnar: nasal cav, pharynx, urethra Stratified transitional: bladder lining Pseudostrat: trachea

2. Connective Tissue

Most abundant

Varied appearance/function

Each type has unique matrix

Types of Connective Tissue

a. Blood/lymph: liquid matrix b. Areolar: loose conn tiss c. Adipose: fat tissue d. Fibrous: bundles of collagen fibers e. Bone: cells in calcified matrix f. Cartilage: matrix is softer, flexible protein g. Hematopoietic: red marrow

3. Muscular Tissue Cardiac, Skeletal, Smooth

4. Nervous or Neural Tissue Located in nerves, brain and spinal cord

Neurons and Glial cells