Tissues of the Body

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

Four Basic Kinds of Tissues Epithelial Tissue Epithelial Tissue Connective Tissue Connective Tissue Muscle Tissue Muscle Tissue Nervous Tissue Nervous Tissue

Epithelial Tissue Epithelial Tissue Locations: Epithelial Tissue Locations: Covers the body Covers the body Lines the cavities, tubes, ducts and blood vessels inside the body Lines the cavities, tubes, ducts and blood vessels inside the body Covers the organs inside body cavities Covers the organs inside body cavities Epithelial Tissue Functions: Epithelial Tissue Functions: Protection from physical & chemical injury, Protection from physical & chemical injury, Protection against microbial invasion, Protection against microbial invasion, Contains receptors which respond to stimuli, Contains receptors which respond to stimuli, Filters, secretes & reabsorbs materials and Filters, secretes & reabsorbs materials and Secretes serous fluids to lubricate structures. Secretes serous fluids to lubricate structures.

Connective Tissue Connective Tissue: Connective Tissue: Most abundant & widely distributed tissue Most abundant & widely distributed tissue Connective Tissue Functions: Connective Tissue Functions: Connects, binds and supports structures, Connects, binds and supports structures, Tendons, ligaments, etc. Tendons, ligaments, etc. Protects & cushions organs and tissues, Protects & cushions organs and tissues, Insulates (fat) and Insulates (fat) and Transports substances (blood). Transports substances (blood).

Muscle Tissue Muscle Tissue location: Muscle Tissue location: Associated with the bones of the skeleton, the heart and in the walls of the hollow organs of the body. Associated with the bones of the skeleton, the heart and in the walls of the hollow organs of the body. Muscle Tissue Functions: Muscle Tissue Functions: Movement Movement Locomotion Locomotion Maintains posture Maintains posture Produces heat Produces heat Facial expressions Facial expressions Pumps blood Pumps blood Peristalsis( wave- like motion ) Peristalsis( wave- like motion )

Nervous Tissue Nervous Tissue location: Nervous Tissue location: Main component of the nervous system, Main component of the nervous system, ie., brain, spinal cord & nerves. Nervous Tissue Functions: Nervous Tissue Functions: Regulates & controls body functions Regulates & controls body functions Generates & transmits nerve impulses Generates & transmits nerve impulses Supports, insulates and protects impulse generating neurons. Supports, insulates and protects impulse generating neurons.

Different types of Epithelium

Squamous Epithelium Simple – one cell thick Lines blood vessels, body cavities & cover organs in body cavities Lines blood vessels, body cavities & cover organs in body cavities Stratified – multiple layers Stratified – multiple layers Forms epidermis Forms epidermis

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

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 Pseudostratified – gives the appearance of more than one layer of columnar epithelial cells

Specific Connective Tissue Types: Specific Connective Tissue Types: Adipose Adipose Bone Bone Hyalaine cartilage Hyalaine cartilage

Connective - Adipose Stores energy (fat) Stores energy (fat) Insulates Insulates Supports & protects organs Supports & protects organs

Connective - Bone Supports & protects Supports & protects Mineral storage Mineral storage Fat storage Fat storage Blood cell production Blood cell production

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

Muscle Tissue Types: Consists of specialized cells that contract when stimulated Consists of specialized cells that contract when stimulated The body has three types of muscle tissue: The body has three types of muscle tissue: Skeletal (voluntary) Skeletal (voluntary) Cardiac (involuntary) Cardiac (involuntary) Smooth muscle (involuntary) Smooth muscle (involuntary)

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

Specific Nervous Tissue Types Nervous – Neuron Conducting cells, called neurons, transmit impulses from one region of the body to another. Nonconducting cells, neuroglia, are a type of nervous system connective tissue.

Membranes Sheets of tissue that cover or line surfaces or that separate organs, or parts of organs from one another. Sheets of tissue that cover or line surfaces or that separate organs, or parts of organs from one another. Mucous – line cavities or passages of the body that open to the exterior such as mouth, esophagus, digestive tract, respiratory passages Mucous – line cavities or passages of the body that open to the exterior such as mouth, esophagus, digestive tract, respiratory passages Function in protection, secretion of mucus, and absorption Function in protection, secretion of mucus, and absorption Cutaneous Membrane- Covers the body Are continuous with mucous membranes

Serous line closed cavities of the body such as thoracic cavity (pleura), Abdominal cavity (peritoneum), and sac in which heart lies (pericardium) line closed cavities of the body such as thoracic cavity (pleura), Abdominal cavity (peritoneum), and sac in which heart lies (pericardium) Also cover organs lying in those closed cavities Also cover organs lying in those closed cavities Has two layers Has two layers Visceral – covers organs Visceral – covers organs Parietal – lines the cavity Parietal – lines the cavity Potential space between the two layers is kept moist by the secretion of a small amount of serous fluid which prevents friction when the two layers rub together Potential space between the two layers is kept moist by the secretion of a small amount of serous fluid which prevents friction when the two layers rub together

Synovial Membranes- Line joints, tendons, and bursa(A sac containing synovial fluid at sites of friction) Secrete synovial fluid which prevents friction on the smooth, moist surfaces