4-1. 4-2 Chapter 4 Histology 4-3 Tissues and Histology Tissue Level of Organization –Epithelial...
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Transcript of 4-1. 4-2 Chapter 4 Histology 4-3 Tissues and Histology Tissue Level of Organization –Epithelial...
4-1
4-2
Chapter 4
Histology
4-3
Tissues and Histology
• Tissue Level of Organization– Epithelial – Connective– Muscle– Nervous
• Histology: Microscopic Study of Tissues
4-4
Epithelium Characteristics
• Consists almost entirely of cells
• Covers body surfaces and forms glands
• Has free and basal surface
• Specialized cell contacts• Avascular• Undergoes mitosis
4-5
Functions of Epithelia
• Protecting
• Barriers
• Passage of substances
• Secreting
• Absorbing
4-6
Classification of Epithelium
• Simple– Squamous, cuboidal, columnar
• Stratified– Squamous, cuboidal, columnar
• Pseudostratified – columnar
• Transitional– Cuboidal to columnar when not stretched and
squamouslike when stretched
4-7
Types of Epithelium
4-8
Types of Epithelium
4-9
Types of Epithelium
4-10
Types of Epithelium
4-11
Types of Epithelium
4-12
Types of Epithelium
4-13
Types of Epithelium
4-14
Types of Epithelium
4-15
Functional Characteristics• Cell layers and shapes
– Diffusion, Filtration, Secretion, Absorption, Protection
• Cell surfaces– Microvilli: Increase surface area absorption or
secretion
– Cilia: Move materials across cell surface
• Cell connections– Desmosomes, tight, gap
• Glands– Exocrine: Have ducts
– Endocrine: Have no ducts
4-16
Cell Connections
• Functions– Bind cells together
– Form permeability layer
– Intercellular communication
• Types– Desmosomes
– Tight
– Gap
4-17
Exocrine Glands and Secretion Types
• Merocrine– Sweat glands
• Apocrine– Mammary
glands
• Holocrine– Sebaceous
glands
4-18
Connective Tissue
• Abundant
• Consists of cell separated by extracellular matrix
• Diverse
• Performs variety of important functions
4-19
Functions of Connective Tissue
• Enclosing and separating as capsules around organs
• Connecting tissues to one another as tendons and ligaments
• Supporting and moving as bones• Storing as fat• Cushioning and insulating as fat• Transporting as blood• Protecting as cells of the immune system
4-20
Connective Tissue Cells• Specialized cells produce the extracellular matrix
– Suffixes• -blasts:• -cytes: • -clasts:
• Adipose or fat cells• Mast cells that contain heparin and histamine• White blood cells that respond to injury or
infection• Macrophages that phagocytize or provide
protection• Stem cells
4-21
Extracellular Matrix
• Components– Protein fibers
• Collagen
• Reticular
• Elastic
– Ground substance• Shapeless background
– Fluid
4-22
Connective Tissue Categories
• Embryonic or mesenchyme
• Adult– Loose– Dense– Connective tissue with special properties– Cartilage– Bone– Blood
4-23
Loose Connective Tissue
• Areolar tissue• Loose packing material of most organs and tissues• Attaches skin to underlying tissues• Contains collagen, reticular, elastic fibers and variety of cells
4-24
Dense Connective Tissue• Dense regular
– Has abundant collagen fibers• Tendons:
• Ligaments:
• Dense regular elastic
• Dense irregular
• Dense irregular collagenous
• Dense irregular elastic
4-25
Dense Regular Connective Tissue
4-26
Dense Irregular Connective Tissue
4-27
Connective Tissue with Special Properties
• Adipose tissue– Consists of adipocytes– Types
• Yellow (white)• Brown
• Reticular tissue– Forms framework of lymphatic tissue– Characterized by network of fibers and cells
4-28
Adipose Tissue
4-29
Reticular Tissue
4-30
Cartilage
• Composed of chondrocytes located in spaces called lacunae
• Next to bone firmest structure in body
• Types of cartilage– Hyaline– Fibrocartilage– Elastic
4-31
Hyaline Cartilage
• Found in areas for strong support and some flexibility
• Forms most of skeleton before replaced by bone in embryo
• Involved in growth that increases bone length
4-32
Fibrocartilage
• Slightly compressible and very tough• Found in areas of body where a great deal of pressure
is applied to joints
4-33
Elastic Cartilage
• Rigid but elastic properties
4-34
Bone
• Hard connective tissue that consists of living cells and mineralized matrix
• Organic and inorganic
• Types– Cancellous or spongy bone– Compact bone
4-35
Bone
4-36
Blood
• Matrix between the cells is liquid
• Hemopoietic tissue– Forms blood cells
– Found in bone marrow
4-37
Bone Marrow
4-38
Muscle Tissue
• Characteristics– Contracts or shortens with force– Moves entire body and pumps blood
• Types– Skeletal– Cardiac– Smooth
4-39
Skeletal Muscle
4-40
Cardiac Muscle
4-41
Smooth Muscle
4-42
Nervous Tissue
• Found in brain, spinal cord and nerves
• Ability to produce action potentials
• Cells– Nerve cells or neurons
• Consist of dendrites, cell body, axons
• Consist of multipolar, bipolar, unipolar
– Neuroglia or support cells
4-43
Neurons
4-44
Neuroglia
4-45
Membranes
• Mucous• Serous• Synovial
4-46
Inflammation• Response when tissues
damaged or with an immune response
• Manifestations– Redness, heat, swelling,
pain, disturbance of function
• Mediators– Include histamine, kinins,
prostaglandins, leukotrienes
4-47
Tissue Repair• Substitution of viable cells for dead cells• Skin repair
– Primary union: Edges of wound close together• Wound fills with blood
• Clot forms
• Scab
• Pus
• Granulation tissue
• Scar
– Secondary union: Edges of wound not close• Clot may not close gap
• Inflammatory response greater
• Wound contraction occurs leading to greater scarring
4-48
Tissue Repair
4-49
Tissues and Aging
• Cells divide more slowly in older than younger people
• Tendons and ligaments become less flexible and more fragile
• Arterial walls become less elastic
• Rate of blood cell synthesis declines in elderly
• Injuries are harder to heal in elderly