Tissues of the Human Body Key Terms Histology

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 n n n Forms solid layer of cells which line blood vessels, body cavities & cover organs in body cavities Stratified – multiple layers Forms epidermis

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

Columnar Epithelium • Simple – one cell thick • Column shaped (long & narrow) • Line digestive tract where reabsorption & secretion occurs. n 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) n n 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 n n Supports & protects Mineral storage Fat storage Blood cell production

Connective – Hyaline Cartilage n n 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 n n n 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 n n 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)