A&P Histology Tissues

Histology Histology is the study of tissues A group of similar cells Ususally have a common embryonic origin Work together to carry out specialized activities What is histology? What is a tissue?

Histology Epithelial: covers body surfaces covers body surfaces Lines hollow organs and body cavities Lines hollow organs and body cavities Forms glands Forms glands What types of tissues are there ?

Histology Connective tisssue protects and supports the body and organs protects and supports the body and organs Binds organs together Binds organs together Stores energy (fat) Stores energy (fat) Provide immunity Provide immunity What types of tissues are there?

Histology Muscular tissue generates force needed to make the body move generates force needed to make the body move What types of tissues are there?

Histology Nervous tissue detects changes inside and outside body detects changes inside and outside body Responds by generating action potentials Responds by generating action potentials Helps maintain homeostasis (constant internal environment) Helps maintain homeostasis (constant internal environment) What types of tissues are there?

Histology Contact points between the plasma membranes of tissue cells Joins cells into functional units Cell junctions

Histology Contain plaque- a dense layer of proteins inside the plasma membrane Plaque attaches to transmembrane proteins and the cytoskeleton Help epithelial cells resist separation Adherens junctions

Classwork/homework Classwork: Copy figure 4.2 on page 85 in blue book (This is 4.1 on page 109 in red book). Include the definitions of tight junction, gap junction, desmosome, hemidesmosome Homework: Read pages Do #1,2 on page 108 and #3,4 on page 110.

Epithelium Cells are closely packed Cell junctions secure cells tightly to each other at lateral (side to side) surfaces Avascular: lacks blood vessels Structural features of epithelium

Epithelium Has nerve supply Microvilli may be present for secretion or absorption Cilia may be present for moving substances along Structural features of epithelium

Epithelium Basal (bottom) surfaces of epithelial cells attach by a basement membrane to underlying connective tissue Basal lamina: membrane made of collagen and laminin, right under epithelial cells Reticular lamina: below basal lamina Basement membrane

Epithelium Single layer of flat cells Centrally located nucleus Function: filtration, diffusion, secretion Found where absorption takes place Also reduces friction (slick, slippery surface) Simple squamous epithelia

Epithelium Single layer of cube shaped cells Centrally located nucleus Function: secretion, absorption Found in pancreas, kidney, ovary Simple cuboidal epithelia

Epithelium Single layer of column like cells Nuclei near base of cells Function: secretion and absorption Simple columnar epithelia

Epithelium Single layer of column like cells Has cilia Nuclei near base Function: moves mucus and other substances Ciliated simple columnar epithelium

Epithelium Not really stratified (layered) All cells attached to basement membrane Nuclei are anywhere Function: secretion, move mucus Pseudostratified columnar epithelium

Epithelium Several layers Basal (bottom) layers are cuboidal Apical layers are squamous Function: protection Stratified squamous epithelia

Classwork/homework Classwork: paste in figure of epithelial cells and label. Include the name of each tissue, one or more location, one or more function. Color (code for yourself) these structures: nucleus, cytoplasm, basement membrane Homework: read pages Do page 121 #7

Connective Tissue Most abundant tissue in body Consists of cells and extracellular matrix Extracellular matrix : protein fibers and ground substance (material between cells and fibers). Extracellular matrix is secreted by the connective tissue, helps determine properties of the tissue Features

Connective Tissue binds together supports strengthens other tissues protects,insulates transport system Functions

Connective Tissue- Types Made of collagen fibers, mast cells, fat cells, fibroblasts, macrophages, elastic fibers Found beneath dermis of skin, digestive/respiratory/urinary tracts, between muscles, around blood vessels, around joints Function: protection (physical, immunity) and support Loose Connective Tissue

Connective Tissue- Types Made of adipocytes (fat cells) Found beneath dermis of skin, behind eyeballs, around kidneys. Function: protection (physical), insulation, energy storage Adipose

Connective Tissue- Types Made of collagen fibers Found in tendons, ligaments, covering skeletal muscles and organs Function: attachment, movement, reduce friction, stabilization Dense connective tissue

Connective Tissue- Types Made of ground substance, collagen fibers, chondrocytes (cartilage cells) Found around bones Function: support, reduces friction, prevents bone-to- bone contact Cartilage

Connective Tissue- Types Made of osteocytes (bone cells), blood vessels Found in skeletal system, ear Function: support, protection, blood formation, movement Bone

Connective Tissue- Types Made of blood plasma, red blood cells, white blood cells, platelets Found within blood vessels Function: transport gases, immunity, repair Liquid connective tissue

Classwork/Homework Classwork: Label figures with name of tissue, one or more location, one or more function. Color (you decide color code) these structures: nucleus, cytoplasm, fat globule (H only) Homework: read pages Do page 132 #13

Muscle Tissue Elongated cells called muscle fibers. Produces body movements, maintains posture, generates heat, provides protection Features Functions

Muscle Tissue Attached to bones Striations- alternating light and dark bands Voluntary Skeletal muscle tissue

Muscle Tissue Forms most of the wall of the heart Muscle fibers are branched StriationsInvoluntary Cardiac muscle tissue

Muscle Tissue Found in the walls of hollow internal structures (blood vessels, airways, the stomach, etc) Lack striations Involuntary Function: control flow of fluids through these areas Smooth muscle tissue

Nervous Tissue Made of neurons (nerve cells) and neuroglia (support cells). Found throughout the nervous system Function: convert stimuli/responses to action potentials Nervous tissue

Classwork/Homework Classwork: paste in figure of muscle and nerve cells and label. Include the name of each tissue, one or more location, one or more function. Homework: RED BOOK read pages Do pages 136 #12,18 and 127 #19

Additional Vocabulary A type of loose connective tissue. It contains many types of cells (fibroblasts, white blood cells, etc) as well as fibers. Forms the subcutaneous layer with addipose. Areolar Connective Tissue

Additional Vocabulary Ground substance, gel. Appears bluish white, shiny. Hyaline cartilage

Additional Vocabulary Regular: arranged in parallel patterns. Found in tendons and ligaments. Irregular: not parallel. Found beneath skin, around muscles and organs. Dense Connective Tissue (Regular vs Irregular)