Chapter 3 Cells and Tissues

Anatomy of a Cell• Plasma Membrane “cell”– Fluid Mosaic Model• Phospholipids – cushioning insulation• Proteins – growth maintenance and repair• Both are double layered

• Specializations–Microvilli – tiny projections that absorb

nutrients–Membrane Junctions

Membrane Transport• Semipermeable– Allows only certain substance in and out

• Passive Processes– Simple diffusion – higher concentration to

lower concentration

– Osmosis – diffusion of H2O

– Facilitated diffusion – carrier molecules speed up diffusion rate.

– Filtration - kidneys

Membrane Transport Cont..

• Active Transport– cell uses energy (lower to higher)– Active processes – move against a

concentration gradient– Bulk transport

• Exocytosis – large particles leave cell

• Endocytosis– Phagocytosis – engulfs large solids– Pinocytosis – engulfs large liquids

Cellular Organization• Cytoplasm – jelly like material in cells

– 70% H20, 30% proteins lipids minerals

• Organelles– Mitochondria

• “powerhouse” • “cellular respiration” • makes energy ATP

– Ribosomes• Makes “protein synthesis”

– Endoplasmic Reticulum• “canal systems”• Rough E.R. – transport proteins• Smooth E.R. – make lipids & transport them

More Cellular Organization• Golgi Apparatus

– Package and store proteins, lipids, carbohydrates

• Lysosomes– Digestive organelles

• Vacuoles– Storage organelles

• Cytoskeletal– Support cell, protein filaments

• Centrioles– Cell division, cylinders

Nucleus – control center• Nuclear Membrane• Nucleoli (nucleolus)– makes ribosomes & RNA

• Chromatin– Thread like– All chromosomes in a strand– DNA – heredity (code of life)

Cell Growth & Reproduction

• Cell Life Cycle– Interphase – “resting” normal replicate DNA

• Mitosis – cell division– Prophase

• Spindle fibers, centrioles migrate• Nucleus fades• Chromosomes shortened, thickened & doubled

– Metaphase• Paired chromosomes• (chromatids) line up in middle of the cell• Centromere- attaches chromatids to spindle fibers

Cell Growth & Reproduction cont…

– Anaphase• Pairs split apart• Single strands migrate to each end

– Telophase – cell membrane pinches in• Cytokinesis – cell divides• Two new cells are formed- daughter cells

Cell Growth & Reproduction Cont..

• Protein Synthesis– DNA• Deoxyribonucleic acid, codes heredity

– RNA• Transfer -- translate code• Messenger -- read code

– Transcription – A-T U A– Translation - C-G G C (Serine)

» G-C C G» Ribosomal -- make proteins

Epithelial Tissues– Primary Functions

• Protection• Absorption• Filtration• Secretion

• Features of Epithelial Cells– Cell Junctions – close– One cell surface is free

• Apical – exposed to surface or cavity

Epithelial Cont..– Basement membrane – lowest surface– Avascular – no blood supply, diffusion– Regeneration – easy fast, mitosis

• Cell Shapes– Squamous

• Scale, flattened

– Cuboidal• Cube shaped

– Columnar• Taller than wide

Types of Epithelial Tissues

• Simple– Single layer

• Stratified–Many layers

• Pseudostratified– Looks like many layers- is really only one

Epithelial cont• Simple Squamous

– One layer– Filtration– Diffusion– Locations: Pericardium,Pleura, Alveoli, Capillary walls

• Simple Cuboidal– One layer– Cube shaped– Locations: Ducts of glands,Salivary & sweat glands, Covering ovary

More Body Tissues• Simple Columnar

Taller than wide– Line digestive tract– Goblet cells

Secrete mucus

• Pseudostratified ColumnarOne cell layer(looks like more)– Ciliated w/Goblet cells– Line respiratory tract

Body Tissues• Stratified Squamous– Several layers– Located: Rectum, SkinLining of mouth, top third of esophagus

• Transitional– Located: – bladder, uterus– Stretched – one layer– Relaxed – many layers

Body Tissues• Glandular Epithelial- secretes– Endocrine “in”• Ductless• Hormones -- blood

– Exocrine “out”• Ducts

– Lined with stratified cuboidal or stratified columnar

– Sweat, salivary, oil glands, bile duct, pancreatic duct

Connective Tissues• Functions

• Protects• Supports• Connects & binds

– Vascularized• Good blood supply• Except for …

– Tendons– Ligaments– Cartilage have none

– Extracellular matrix• Non living

– Liquid– Gel solid– Semi solid– solid

Body Tissues– Fibers• Collagen - protein

– White- strength

Elastin– Yellow- stretch

– Specialized Cells• Fibroblasts- make fibers• Osteocytes- bone cells• Chondrocytes- cartilage cells• Macrophages- engulf bacteria

• Types of Connective Tissue– Loose – areolar (most common)• Matrix : liquid• Fibers: collagen & elastin• Cells: fibroblasts,• macrophages, • fat cells, • plasma cells

– Dense – “fibrous” poor blood supply• Collagen fibers few fibroblasts• Tendons – bone to muscle• Ligaments- bone to bone

• Adipose – “fat”– Large vacuole w/ droplet of oil– Subcutaneous layer around organs– Insulation– Cushion– Store energy

Cartilage – no blood supplyCartilage cells in gel matrixCollagen & elastin fibersTypes

Hyaline – glassy “blue”Outer noseLarynxRibFetus

Elastin –mostly elastin fibersOuter earEpiglottis

Fibrocartilage – collagen & found in vertebral discs & knees

• Bone – “osseous”• Bone cells- osteocytes– Collagen fibers– Solid matrix – Ca & P

• Blood – “liquid”– Blood cells

• Red• White• platelets

– Fluid matrix• Plasma• Fibers

• Muscle Tissue– Skeletal – striated• Striations• Voluntary• Attached to bone Gross movements

– Cardiac• Striations• Branching• Involuntary• Heart

– Smooth Muscle• No striations• Involuntary• Blood vessels• Organs of digestion• Peristalsis

• Nervous Tissue– Functions• Irritability • “react to stimuli”• Conductivity – flow of ions Na+ & K+

Tissues• Tissue Repair–Regeneration•Mitosis• Replacement w/ same type of cell

–Fibrosis• Scar tissue• Repair w/ fibrous connective tissue

Tissues

• Developmental Aspects– Growth• mitosis

– Aging• Collagen fibers loss• Muscle-loss• Bone-loss• Thinning of epithelial

Tissues• Neoplasms– Cancerous

• Abnormal growth rapidly dividing cells– Benign – stopped– Malignant – still undergoing rapid mitosis

– Hyperplasia• Enlargement of body tissue

– Atrophy• Decrease in size (muscle)

– Hypertrophy-increase