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
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•
•
•
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 Columnar
One cell layer(looks like more)
– Ciliated w/Goblet cells
– Line respiratory tract
Body Tissues
• Stratified Squamous
– Several layers
– Located: Rectum, Skin
Lining of mouth, top third of esophagus
• Transitional
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–
–
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
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Fibroblasts- make fibers
Osteocytes- bone cells
Chondrocytes- cartilage cells
Macrophages- engulf bacteria
• Types of Connective Tissue
– Loose – areolar (most common)
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•
•
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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 supply
Cartilage cells in gel matrix
Collagen & elastin fibers
Types
Hyaline – glassy “blue”
Outer nose
Larynx
Rib
Fetus
Elastin –mostly elastin fibers
Outer ear
Epiglottis
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
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•
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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