Chapter 04 Lecture Outline See separate Power Point

Chapter 04 Lecture Outline See separate Power. Point slides for all figures and tables preinserted into Power. Point without notes. Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. 1

Introduction to Body Tissues 1. Composed of specialized cells of similar structure and perform a common function 2. Four major types (4 C’s mnemonic) a. Epithelial - Cover b. Connective - Connect c. Muscular - Contract d. Nervous - Communicate 3. Organs are typically composed of all four types of tissue 2

4. 1 Epithelial Tissue 3

A. General characteristics 1. 2. 3. 4. 5. 6. 7. Cells are tightly packed Protects external and internal body surfaces Also secretes and absorbs substances Epithelial cells readily divide to replace lost or damaged cells Cells are avascular (lack a blood supply) Has a free surface and a basement membrane Classified by cell shape and the number of cell layers 4

B. Classification of Epithelial Tissue 1. Number of cell layers a. Simple epithelial tissue is one cell layer thick b. Stratified epithelial tissue is composed of two or more layers 2. Shape of the cells a. Squamous epithelium has flattened cells b. Cuboidal epithelium has cube-shaped cells c. Columnar epithelium has elongated cells 3. Two additional special tissues 5

C. Squamous epithelium 1. Simple squamous epithelium a. Composed of a single layer of flattened cells b. Found in areas where simple diffusion occurs – alveoli, capillaries 6

Simple squamous epithelium 7

Squamous epithelium, cont 2. Stratified squamous epithelium a. Has many cell layers b. Shape of deeper cells may be cuboidal or columnar c. Shape of outer cells are flattened and squamous-shaped d. Found in the outer portion of the skin and in body orifices 8

Stratified squamous epithelium 9

D. Cuboidal epithelium 1. Simple cuboidal epithelium a. Single layer of cube-shaped cells attached to a basement membrane b. Found in glands where its function is secretion c. Cells have many mitochondria to produce ATP d. Free surface may have microvilli e. Covers the ovaries f. Lines most of the kidney tubules where it absorbs and secretes substances 10

Cuboidal epithelium, cont 2. Stratified cuboidal epithelium a. Often only has two layers b. Mostly found lining the larger ducts of certain glands 11

Simple Cuboidal epithelium 12

E. Columnar epithelium 1. Simple columnar epithelium a. Cells are longer than they are wide b. Modified to perform particular functions c. Some cells are goblet cells that secrete mucus or have microvilli d. Lines digestive organs and the uterine tubes 2. Stratified columnar epithelium a. Not very common b. Located in parts of the pharynx and in 13

Simple columnar epithelium 14

F. Pseudostratified columnar epithelium 1. Appears to have more than one layer of cells, but only has one true layer 2. Each cell touches the basement membrane 3. Pseudostratified ciliated columnar epithelium lines parts of the reproductive system and air passageways of the respiratory system 4. Contains goblet cells and cilia 15

Pseudostratified ciliated columnar epithelium 16

G. Transitional epithelium 1. Changes in response to tension from cuboidal to squamous cells 2. Located in urinary bladder, the ureters, and part of the urethra 3. Allows these organs to stretch 4. Cells are physically able to slide in relation to one another 17

Epithelial Tissue 18

4. 2 Connective Tissue 19

A. General characteristics 1. Binds structures together, provides support and protection, fills spaces, produces blood cells, and stores fat 2. Cells are separated by an extracellular matrix (nonliving) that is composed of an organic ground substance that contains the following fibers: a. Collagen fibers b. Elastic fibers c. Reticular fibers 20

B. Fibrous Connective Tissue 1. Loose (areolar) connective tissue a. Cells of this tissue are mainly fibroblasts b. Contains many collagen and elastin fibers in a fine web like arrangement c. Adipose tissue is a type of loose connective tissue in which the cells enlarge and store fat 21

Loose (areolar) connective tissue 22

Adipose Tissue 23

2. Dense Connective Tissue a. Has thick bundles of collagen fibers b. In dense regular connective tissue the bundles are parallel (as in tendons, ligaments, and aponeuroses) c. In dense irregular connective tissue the bundles run in different directions (in the dermis and joint capsules) d. In reticular connective tissue the cells are called reticular cells and the matrix contains only reticular fibers (also called lymphatic tissue) 24

Dense regular connective tissue 25

Dense irregular connective tissue 26

C. Connective tissue - Cartilage 1. Cells called chondrocytes are found in small chambers called lacunae; chondroblasts produce the cartilage tissue 2. Because it is avascular, it heals slowly 3. Hyaline cartilage a. Most common type b. Contains only collagen fibers c. Found in the nose, ends of long bones and ribs, in the supporting rings of the trachea, and the embryonic skeleton 27

Cartilage, cont 4. Elastic cartilage a. Matrix contains many elastic fibers; also contains collagen fibers; more flexible than hyaline cartilage b. Found in the outer ear 5. Fibrocartilage a. Matrix contains strong collagen fibers b. Absorbs shock c. Found between the vertebrae and in the knee joint 28

Three types of cartilage 29

D. Connective tissue - bone 1. 2. 3. 4. Extremely hard matrix composed of mineral salts deposited around collagen fibers Bones cells – osteoblasts produce the organic part of bone, then become osteocytes Compact bone – Haversian systems Spongy bone – trabeculae and bone marrow 30

Bone tissue 31

E. Connective Tissue - Blood 1. Composed of formed elements (cells) a. Red blood cells (erythrocytes) - carry oxygen b. White blood cells (leukocytes) – fight infection c. Platelets (thrombocytes) – blood clotting 2. Liquid matrix is called plasma and is not formed by the tissue cells 32

Blood 33

Classification of Connective Tissue 34

4. 3 Muscular Tissue 35

1. General characteristics 1. 2. Cells are called fibers because they are long Cells contain actin and myosin which are contractile proteins 36

B. Skeletal Muscle Tissue 1. 2. 3. 4. 5. 6. Voluntary muscle Attached to bones of the skeleton by tendons Contraction causes movement of body parts Have a cylindrical shape and are long Muscle fibers (cells) have multiple, peripherally located nuclei Muscle fibers appear striated due to the placement of actin and myosin filaments in the fiber 37

Skeletal Muscle 38

C. Smooth Muscle Tissue 1. 2. 3. 4. 5. Visceral muscle – found in the walls of hollow viscera (organs) Spindle-shaped cells with one central nucleus Under involuntary control No striations Contract rhythmically, on its own, but can be modified by the nervous system 39

Smooth Muscle 40

D. Cardiac Muscle Tissue 1. 2. 3. 4. 5. 6. Found only in the walls of the heart Pumps blood Cardiac muscle cells have striations, like skeletal muscle Is involuntary, like smooth muscle Cardiac muscle cells have a single, centrally located nucleus and are branched Cardiac muscle cells are bound to one another by intercalated disks 41

Cardiac Muscle 42

Classification of Muscular Tissue 43

4. 4 Nervous Tissue 44

A. Neurons 1. 2. Found in the brain and spinal cord Neurons (nervous tissue cells) generate and conduct nerve signals. 3. A neuron has three parts: a. Dendrite – receives an impulse b. Cell body – contains the nucleus c. Axon – conducts nerve impulses 4. Long axons are called fibers and form tracts in the brain and spinal cord and nerves in the body 45

Nervous Tissue 46

B. Neuroglia 1. 2. More numerous nervous tissue cells Support and nourish neurons, but do not conduct an impulse 3. Types of neuroglia found in the brain: a. Microglia – engulf bacteria and cellular debris b. Astrocytes – produce glial-derived growth factor c. Oligodendrocytes – form the myelin sheath d. Ependymal cells – line the ventricles 4. Schwann cells are neuroglia located outside the brain or spinal cord that produce the myelin sheath around nerves 47

4. 5 Extracellular Junctions, Glands, and Membranes 48

A. Extracellular Junctions 1. Junctions between cells help cells function as a tissue 2. Types of cell junctions: a. Tight junction – plasma membrane proteins join, forming an impermeable barrier b. Gap junction – plasma membrane channels join, allowing substances to pass between the two cells c. Adhesion junction (desmosome) – adjacent plasma membranes held together by extracellular filaments 49

Extracellular Junctions 50

B. Glands 1. Consists of one or more cells that produce and secrete a product 2. Most are composed primarily of epithelium 3. Exocrine glands – secrete their product onto the outer surface or into a cavity a. Examples include Goblet cells and sweat glands 4. Endocrine glands are ductless and secrete their product internally to be transported by the bloodstream a. Examples include the pituitary and thyroid glands 51

Multicellular Exocrine Glands 52

C. Membranes 1. Mucous membranes a. Line interior walls of the organs and tubes that open to the outside of the body – digestive, respiratory, urinary, and reproductive systems b. Consist of epithelium overlying a layer of loose connective tissue c. Epithelium contains goblet cells that secrete mucus 53

2. Serous Membranes a. Parietal membranes line thoracic and abdominopelvic cavities b. Visceral membranes cover internal organs c. Consist of a layer of simple squamous epithelium overlying a layer of loose connective tissue d. Secrete serous fluid that lubricates the membranes e. Pleura – serous membranes in the thorax 1) Parietal pleura – lines thoracic wall 2) Visceral pleura – covers the surface of the lungs 54

Serous membranes, cont f. Pericardium – covers the heart (also double) g. Peritoneum – serous membranes within the abdomen 1) Parietal peritoneum – lines the abdominopelvic wall 2) Visceral peritoneum – covers the organs in the abdominopelvic cavity 55

Membranes, cont 3. Synovial membranes a. Line freely movable joint cavities b. Composed of connective tissue c. Secrete synovial fluid that lubricates the ends of bones 4. Meninges a. Found within the posterior cavity b. Composed entirely of connective tissue c. Protective covering for the brain and spinal cord 56

Membranes, cont 5. Cutaneous membrane (skin) a. Forms the outer covering of the body b. Consists of an outer portion of keratinized stratified squamous epithelium attached to a thick layer of dense connective tissue 57