Tissues of the Body

Histology: the study of tissues.

From Cells to Organ Systems Cells combine to form tissues, and tissues combine to form organs

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

structure and function… Diversity in structure and function… anatomy & physiology!

Crash Course Intro to TISSUES https://www.youtube.com/watch?v=i5tR3csCWYo

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 Protection against microbial invasion Contains receptors which respond to stimuli Filters, secretes & reabsorbs materials Secretes serous fluids to lubricate structures

Epithelium Two FUNCTIONAL types: membranous epithelia form the coverings or linings of organs glandular epithelia form exocrine and endocrine glands

Epithelium SHAPE LAYERS STRUCTURAL types: Squamous Simple Cuboidal Columnar Stratified LAYERS

Epithelium-Human Stomach

Glandular Epithelia

Figure 4.4

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

Connective Tissue Binds the cells and organs of the body together Section 4-1 Binds the cells and organs of the body together All connective tissues consist of two basic components: cells and extracellular matrix (fibers) Two types of connective tissue are: Connective tissue proper Specialized connective tissue

Connective Tissue

Connective Tissue Loose connective tissue Dense connective tissue An important structural component of organs Consists of two types: Loose connective tissue Dense connective tissue

Specialized Connective Tissues Perform specific functions essential to homeostasis The body contains three types of specialized connective tissue: Consists of bone cells (osteocytes) and a calcified cartilage matrix Two types: spongy compact Consists of specialized cells embedded in a matrix of extracellular fibers and other extracellular material BLOOD BONE CARTILAGE Contains blood cells, platelets, plasma

Muscle Tissue Muscle Tissue: Muscle Tissue Functions: Associated with the muscle of the skeleton, the heart and in the walls of the hollow organs of the body. Muscle Tissue Functions: Movement - Locomotion Maintains posture Produces heat Facial expressions Pumps blood Peristalsis = movement of substances through body (i.e. swallowing, intestinal, ovulation)  

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

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

Nervous Tissue Contains specialized cells that conduct impulses 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.

Nerve Tissue

TISSUE LAB EPITHELIAL (2) CONNECTIVE (2) You will view MUSCLE (1) 6 Stratified squamous Simple columnar Pseudostratified columnar CONNECTIVE (2) Adipose Blood Bone Hyaline Cartilage MUSCLE (1) Smooth Skeletal Cardiac NERVOUS (1) Motor neuron You will view 6 of the following:

Tissue Repair (Wound Healing) Regeneration Replacement of destroyed tissue by the same kind of cells No clotting; no scar Fibrosis Repair by dense (fibrous) connective tissue Scar tissue results Determination of method Type of tissue damaged Severity of the injury

Events in Tissue Repair 1. Capillaries become very permeable Introduce clotting proteins A clot walls off the injured area 2. Formation of granulation tissue Growth of new capillaries Rebuild collagen fibers 3. Regeneration of surface epithelium Scab detaches

Tissues that regenerate very well Epithelial tissue (skin and mucous membranes) Fibrous connective tissues (areolar, dense) Bone Blood forming

Tissues that cannot regenerate at all Cardiac muscle Nervous tissue within the brain and spinal cord

- Dense regular Moderate regeneration - Smooth Weak regeneration Skeletal muscle Cartilage

Scar Tissue Build up of scar tissue obstructs or limits movements of smooth muscle. Example: 1. Stomach – churning and twisting of foodstuffs 2. Blood vessels – constricting to move blood through