Tissues of the Human Body

Key Terms Histology: the study of tissues. Tissues: groups of cells which are similar in structure and which perform common or related functions.

4 primary types of tissues Epithelial Connective Nervous Muscle

Epithelial Tissue Epithelial Tissue Locations: Covers the body Lines the cavities, tubes, ducts and blood vessels inside the body Covers the organs inside body cavities

Epithelial Tissue Epithelial Tissue Functions: Protection from physical & chemical injury,

Epithelial Tissue Epithelial Tissue Functions: Protection against microbial invasion,

Epithelial Tissue Epithelial Tissue Functions: Contains receptors which respond to stimuli,

Epithelial Tissue Epithelial Tissue Functions: Filters, secretes & reabsorbs materials and Secretes serous fluids to lubricate structures.

Epithelial Fit closely together to form sheets and bound together by cell junctions Have free surface

Epithelial Lower surface rests on basement membrane, an unstructured material secreted by cells Avascular and depend on diffusion from capillaries in underlying tissues for nutrients

Epithelial Simple=one layer cells Stratified=multiple layers of cells Shape= squamous, cuboidal, columnar

Squamous Epithelium Simple – one cell thick Forms solid layer of cells which line blood vessels, body cavities & cover organs in body cavities Stratified – multiple layers Forms epidermis

Cuboidal Epithelium Simple – one cell thick Roughly cube shaped Cuboid Cells Simple – one cell thick Roughly cube shaped Duct Line ducts in kidneys, etc, where reabsorption and secretory activities take place. Cuboid Cells Duct

Columnar Epithelium Simple – one cell thick Column shaped (long & narrow) Line digestive tract where reabsorption & secretion occurs. Pseudostratified – gives the appearance of more than one layer of columnar epithelial cells

Muscle Tissue Muscle Tissue: Associated with the bones of the skeleton, the heart and in the walls of the hollow organs of the body.

Muscle Tissue Muscle Tissue Functions: Movement Locomotion Maintains posture Produces heat Facial expressions Pumps blood Peristalsis

Muscle Tissue Types Smooth Cardiac Skeletal

Smooth Muscle Given name b/c no stripes

Smooth Muscle Have single nucleus and are spindle-like (pointed ends)

Smooth Muscle Found in walls of hollow organs like stomach, bladder, uterus and blood vessels

Smooth Muscle Peristalsis (wave like motion) created to propel food through digestive tract.

Cardiac Found only in heart Has stripes (striations)

Cardiac Uni-nucleate Branching cells that fit together tightly at intercalated disks (think clasped fingers)

Skeletal Controlled voluntarily

Skeletal Cells are long and cylindrical Multi-nucleate Striped (striations)

Muscle - Skeletal Muscle fibers (cells) long, parallel & cylindrical With many nuclei (multinucleate) Striations (cross stripes run perpendicular to the cells Produce voluntary movement Locomotion Heat

Connective Tissue Connective Tissue: Most abundant & widely distributed tissue

Connective Tissue Functions Connects, binds and supports structures, Tendons, ligaments, etc.

Connective Tissue Functions Protects & cushions organs and tissues,

Connective Tissue Functions Insulates (fat)

Connective Tissue Functions Transports substances (blood).

Connective Tissue Variations in blood supply Well vascularized Exceptions: tendons and ligaments have poor blood supply and cartilage is avascular

Connective Tissue Extracellular matrix -varying amounts of nonliving substances secreted to outside of cells

Extracellular Matrix Produced by the cells involved and then secreted Its what makes the connective tissues different

Extracellular Matrix Composed of nonstructured ground substance and fibers

Types of Connective Tissue Bone Cartilage Dense fibrous (tendons and ligaments)

Connective - Bone Tree ring-like appearance Supports & protects Mineral storage Fat storage Blood cell production

Connective – Hyaline Cartilage Supports while providing flexibility Absorbs compression between bones in joints (articular cartilage) Holds open respiratory passages Most abundant type of cartilage in body

Types of Connective Tissue Areolar (loose, many fibers)

Types of Connective Tissue Adipose (fat tissue)

Connective - Adipose Honeycomb or chickenwire appearance Stores energy (fat) Insulates Supports & protects organs

Types of Connective Tissue Reticular: lymph nodes, spleen, and bone marrow

Types of Connective Tissue Blood

Nervous Tissue Nervous Tissue: Main component of the nervous system, i.e., brain, spinal cord & nerves.

Nervous Tissue Functions Regulates & controls body functions Generates & transmits nerve impulses

Nervous Tissue Functions Supports, insulates and protects impulse generating neurons.

Specific Nervous Tissue Types Nervous – Neuron Branching cells with many long processes Large central nucleus Transmit impulses from one area of the body to other areas Regulate activities through neuron impulses

Specific tissue types & representative cell types we will review: epithelial Squamous Cuboidal Columnar connective Adipose Bone Hyalaine cartilage muscle nervous

Specific Connective Tissue Types: Adipose Bone Hyalaine cartilage

Specific Muscle Tissue Types: muscle (skeletal)