Tissues

10/6/20152 What is Histology? Study of Tissues

Tissues Groups of cells similar in structure and function Types of tissues –Epithelial tissue –Connective tissue –Muscle tissue –Nerve tissue

Tissues

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Four Types of Tissues Types of tissue –Epithelial tissue Covers exposed surfaces Lines internal passageways Forms glands

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Four Types of Tissues Types of Tissue (cont’d) –Connective tissue Fills internal spaces Supports other tissues Transports materials Stores energy –Muscle tissue Specialized for contraction Skeletal muscle, heart muscle, and walls of hollow organs –Neural tissue Carries electrical signals from one part of the body to another

Figure 4.1 Nervous tissue: Internal communication Brain, spinal cord, and nerves Muscle tissue: Contracts to cause movement Muscles attached to bones (skeletal) Muscles of heart (cardiac) Muscles of walls of hollow organs (smooth) Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters Skin surface (epidermis) Lining of GI tract organs and other hollow organs Connective tissue: Supports, protects, binds other tissues together Bones Tendons Fat and other soft padding tissue

Epithelial Tissue

10/6/2015copyright (your organization) Forms the coverings of all of the body’s surfaces Lines body cavities Functions: –Protection –Secretion –Absorption –Excretion –Filtration –Diffusion –Sensory Reception

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia Singular epithelium; plural epithelia Classes of Epithelia –Based on shape Squamous epithelia: thin and flat Cuboidal epithelia: square shaped Columnar epithelia: tall, slender rectangles –Based on layers Simple epithelium: single layer of cells Stratified epithelium: several layers of cells

Figure 4.2a Stratified Simple Apical surface Basal surface Apical surface Basal surface (a) Classification based on number of cell layers.

Figure 4.2b Squamous Cuboidal Columnar (b) Classification based on cell shape.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia

10/6/2015copyright (your organization) Types of Epithelial Tissue

10/6/2015copyright (your organization) Simple Squamous Allows for diffusion, filtration, and osmosis Examples: –Lines heart –Lines Blood vessels –Lines Alveoli

Epithelia: Simple Squamous Figure 4.2a

10/6/2015copyright (your organization) Stratified Squamous Lining of smooth muscles Superficial layer of skin Esophagus, mouth, vagina Aides in protection

Figure 4.3e (e) Stratified squamous epithelium Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers. Function: Protects underlying tissues in areas subjected to abrasion. Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane. Photomicrograph: Stratified squamous epithelium lining the esophagus (285x). Stratified squamous epithelium Nuclei Basement membrane Connective tissue

10/6/2015copyright (your organization) Simple Cuboidal Aides in secretion and absorption Examples –Surface of ovaries –Kidney tubules

Epithelia: Simple Cuboidal Figure 4.2b Single layer of cubelike cells with large, spherical central nuclei Function in secretion and absorption Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface

10/6/2015copyright (your organization) Stratified Cuboidal Aides in protection Examples: –Sweat gland ducts –Male urethra

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia Figure 4–4 Cuboidal Epithelia.

10/6/2015copyright (your organization) Simple Columnar (NON-CILIATED) Lines: –GI tract –Gall bladder Aides in: –Secretion –Absorption

10/6/2015copyright (your organization) Ciliated Simple Columnar Located in: –Respiratory tract –Fallopian tubes –Uterus –Sinuses

Epithelia: Simple Columnar Figure 4.2c

10/6/2015copyright (your organization) Transitional Located in: –Urinary bladder –Uterus –Urethra

Epithelia: Transitional Figure 4.2f Several cell layers, basal cells are cuboidal, surface cells are dome shaped Stretches to permit the distension of the urinary bladder Lines the urinary bladder, ureters, and part of the urethra

10/6/2015copyright (your organization) Pseudostratified Columnar Aides in the movement of material Ciliated  Upper Respiratory tract Non-ciliated  Epididymus and male urethra

Figure 4.3d (d) Pseudostratified columnar epithelium Description: Single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus- secreting cells and bear cilia. Function: Secretion, particularly of mucus; propulsion of mucus by ciliary action. Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract. Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (570x). Trachea Cilia Pseudo- stratified epithelial layer Basement membrane Mucus of mucous cell

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia Figure 4–5 Columnar Epithelia.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Epithelia Figure 4–5 Columnar Epithelia.

Identify the tissues

Connective Tissues

Connective Tissue Most abundant and widely distributed tissue type Four classes –Connective tissue proper –Cartilage –Bone tissue –Blood

Table 4.1

10/6/2015copyright (your organization) Functions Bind structures together Supports the organs and the body (Framework) Stores fat (Insulation) Transports substances (blood) Protects from disease Helps repair tissue damage

Figure 4.7 Macrophage Fibroblast Lymphocyte Fat cell Mast cell Neutrophil Capillary Cell types Extracellular matrix Fibers Collagen fiber Elastic fiber Reticular fiber Ground substance

Connective Tissue Proper Types: –Loose connective tissue Areolar Adipose Reticular –Dense connective tissue Dense regular Dense irregular Elastic

10/6/2015copyright (your organization) Types 1.Areolar (loose) Stretchable, superficial, soft tissue Examples: Surrounds blood vessels and nerves Attaches skin to muscles (Fascia)

Connective Tissue Proper: Loose Figure 4.8b

10/6/2015copyright (your organization) Adipose: Functions –Stores Fats –Protects and supports –Insulates –Food reservoir Located anywhere fat is in excess

Connective Tissue Proper: Loose Figure 4.8c

10/6/2015copyright (your organization) Reticular: Functions –Forms network of spleen, lymph nodes, and bone marrow –Provides defense against microorganisms

Connective Tissue Proper: Loose Figure 4.8d

10/6/2015copyright (your organization) Dense (fibrous): Provide flexible but strong connections Examples: –Tendons (Bone-Muscle) –Ligaments (Bone-Bone) –Aponeuroses (Muscle-Muscle)

Fibrous Connective Tissue Tendons = muscles to bones Ligaments = bones to bones

Connective Tissue Proper: Dense Regular Figure 4.8e

(e) Connective tissue proper: dense connective tissue, dense irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. Function: Able to withstand tension exerted in many directions; provides structural strength. Location: Fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract. Photomicrograph: Dense irregular connective tissue from the dermis of the skin (400x). Collagen fibers Nuclei of fibroblasts Fibrous joint capsule

Figure 4.8f (f) Connective tissue proper: dense connective tissue, elastic Description: Dense regular connective tissue containing a high proportion of elastic fibers. Function: Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration. Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes. Elastic fibers Aorta Heart Photomicrograph: Elastic connective tissue in the wall of the aorta (250x).

10/6/2015copyright (your organization) Bone-> Compact and spongy Blood-> 55% liquid/plasma 45% formed elements Specialized Types

Connective Tissue: Bone (Osseous Tissue) Figure 4.8j

Connective Tissue: Blood Figure 4.8k

10/6/2015copyright (your organization) Cartilage- > Hyaline Fibrous Elastic

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Supportive Connective Tissues Figure 4–14 The Types of Cartilage.

Figure 4.8g (g) Cartilage: hyaline Description: Amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae. Function: Supports and reinforces; has resilient cushioning properties; resists compressive stress. Location: Forms most of the embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larynx. Photomicrograph: Hyaline cartilage from the trachea (750x). Costal cartilages Chondrocyte in lacuna Matrix

Figure 4.8h (h) Cartilage: elastic Description: Similar to hyaline cartilage, but more elastic fibers in matrix. Function: Maintains the shape of a structure while allowing great flexibility. Location: Supports the external ear (pinna); epiglottis. Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (800x). Chondrocyte in lacuna Matrix

Figure 4.8i (i) Cartilage: fibrocartilage Description: Matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate. Function: Tensile strength with the ability to absorb compressive shock. Location: Intervertebral discs; pubic symphysis; discs of knee joint. Photomicrograph: Fibrocartilage of an intervertebral disc (125x). Special staining produced the blue color seen. Intervertebral discs Chondrocytes in lacunae Collagen fiber

10/6/2015copyright (your organization) All have nerve supply (Except Cartilage) Very Vascular (Except Cartilage) All consist of cells and matrix –Matrix=fibers between the cells

Muscle Tissue

10/6/2015copyright (your organization) Components Made up of cells that can shorten or contract in order to produce movement in body parts Well supplied with blood vessels Cells are long and slender (muscle fibers) Actin and myosin are contractile proteins. – myosin.htmlhttp:// myosin.html

10/6/2015copyright (your organization) Types of Muscle Tissues 1.Skeletal->regular (voluntary) Aka. Striated (striped) Many nuclei per cell b/c extremely long 2.Smooth->intestines (involuntary) Non-striated 1.Cardiac->heart (involuntary) Striated

Figure 4.10a (a) Skeletal muscle Description: Long, cylindrical, multinucleate cells; obvious striations. Function: Voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control. Location: In skeletal muscles attached to bones or occasionally to skin. Photomicrograph: Skeletal muscle (approx. 460x). Notice the obvious banding pattern and the fact that these large cells are multinucleate. Nuclei Striations Part of muscle fiber (cell)

Figure 4.10b (b) Cardiac muscle Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs). Function: As it contracts, it propels blood into the circulation; involuntary control. Location: The walls of the heart. Photomicrograph: Cardiac muscle (500X); notice the striations, branching of cells, and the intercalated discs. Intercalated discs Striations Nucleus

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Muscle Tissue Figure 4–18 Muscle Tissue.

Figure 4.10c (c) Smooth muscle Description: Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets. Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passage- ways; involuntary control. Location: Mostly in the walls of hollow organs. Photomicrograph: Sheet of smooth muscle (200x). Smooth muscle cell Nuclei

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Muscle Tissue Figure 4–18 Muscle Tissue.

Nervous Tissue

10/6/2015copyright (your organization) Located in the brain, spinal cord, and nerves Coordinates and controls many of the bodies activities Stimulates muscle contractions Creates awareness Has a role in emotions, memory, and reasoning.

10/6/2015copyright (your organization)

Figure 4.9 Photomicrograph: Neurons (350x) Function: Transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity. Location: Brain, spinal cord, and nerves. Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonirritable supporting cells (not illustrated). Dendrites Neuron processes Cell body Axon Nuclei of supporting cells Cell body of a neuron Neuron processes Nervous tissue

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tissue Injuries and Repair Tissues respond to injuries to maintain homeostasis –Cells restore homeostasis with two processes Inflammation Regeneration

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tissue Injuries and Repair Inflammation = inflammatory response –The tissue’s first response to injury Signs and symptoms of the inflammatory response include –Swelling –Redness –Heat –Pain

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tissue Injuries and Repair Inflammatory Response –Can be triggered by Trauma (physical injury) Infection (the presence of harmful pathogens)

Figure 4.12, step 1 Scab Blood clot in incised wound Epidermis Vein Inflammatory chemicals Inflammation sets the stage: Severed blood vessels bleed and inflammatory chemicals are released. Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area. Clotting occurs; surface dries and forms a scab. Migrating white blood cell Artery 1

Figure 4.12, step 2 Regenerating epithelium Area of granulation tissue ingrowth Fibroblast Macrophage Organization restores the blood supply: The clot is replaced by granulation tissue, which restores the vascular supply. Fibroblasts produce collagen fibers that bridge the gap. Macrophages phagocytize cell debris. Surface epithelial cells multiply and migrate over the granulation tissue. 2

Figure 4.12, step 3 Regenerated epithelium Fibrosed area Regeneration and fibrosis effect permanent repair: The fibrosed area matures and contracts; the epithelium thickens. A fully regenerated epithelium with an underlying area of scar tissue results. 3

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tissue Injuries and Repair Regeneration –When the injury or infection is cleaned up Healing (regeneration) begins

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Aging and Tissue Effects of Aging –Chemical and structural tissue changes Thinning epithelia and connective tissues Increased bruising and bone brittleness Joint pain and broken bones Cardiovascular disease Mental deterioration

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Aging and Tissue Aging and Cancer Incidence –Cancer rates increase with age 1 in 4 people in the United States develops cancer Cancer is the #2 cause of death in the United States Environmental chemicals and cigarette smoke cause cancer

Cell Differentiation All cells carry complete DNA instructions for all body functions Cells specialize or differentiate –To form tissues (liver cells, fat cells, and neurons) –By turning off all genes not needed by that cell All body cells, except sex cells, contain the same 46 chromosomes Differentiation depends on which genes are active and which are inactive

- Cancer What Is Cancer? Cancer is a disease in which cells grow and divide uncontrollably, damaging the parts of the body around them.

Tumors and Cancer Cancer develops in steps –Abnormal cell –Primary tumor –Metastasis –Secondary tumor

Tumors and Cancer Tumor (neoplasm) –Enlarged mass of cells –Abnormal cell growth and division –Benign tumor Contained Not life threatening –Malignant tumor Spreads into surrounding tissues (invasion) Starts new tumors (metastasis)