Body Tissues.pdf

Body Tissues TISSUES ❏ Tissue is a group of cells that have similar structure and that function together as a unit. ❏ a group or mass of similar cells working together to perform common functions. ❏ There are four main tissue types in the body: epithelial, connective, muscle, and nervous. Eac...

Body Tissues TISSUES ❏ Tissue is a group of cells that have similar structure and that function together as a unit. ❏ a group or mass of similar cells working together to perform common functions. ❏ There are four main tissue types in the body: epithelial, connective, muscle, and nervous. Each is designed for specific functions. 4 TYPES OF TISSUES IN THE BODY 01 02 EPITHELIAL TISSUE NERVOUS TISSUE 03 MUSCLE TISSUE 04 CONNECTIVE TISSUE EPITHELIAL TISSUE ● Epithelial tissue is composed of cells laid together in sheets with the cells tightly connected to one another. Epithelial layers are avascular, but innervated. ● Epithelial cells have two surfaces that differ in both structure and function. ● Glands, such as exocrine and endocrine, are composed of epithelial tissue and classified based on how their secretions are released. B. Functions of Epithelium 01 02 03 Protection for the underlying tissues from radiation, desiccation, toxins, and physical trauma 04 Absorption of substances in the The secretion of hormones into the blood vascular system. The secretion of sweat, mucus, enzymes, and other products that are delivered by ducts come from the glandular epithelium. digestive tract lining with distinct modifications. Regulation and excretion of chemicals between the underlying tissues and the body cavity. 05 The detection of sensation. C. Epithelium Characteristics A. Cells fit closely together B.Tissue layer always has one free surface C. The lower surface is bound by a basement membrane D. Avascular (have no blood supply) E. Regenerate easily if well nourished CONNECTIVE TISSUE ❏ Tissue supports, protects, structure to other Did you like thethat resources on this template? Get and them gives for free at our other websites. tissues and organs in the body. ❏ Connective tissue also stores fat, helps move nutrients and other substances between tissues and organs, and helps repair damaged tissue. ❏ Connective tissue is made up of cells, fibers, and a gel-like substance. Types of connective tissue include bone, cartilage, fat, blood, and lymphatic tissue. 2. Connective Tissue -Most abundant tissue in your body, found throughout -Binds structures together -Provides support, protection, framework, fills space, stores fat, produces blood cells, fights infection -Composed of more scattered cells within matrix -Made up of a ground substance and fibers -Most have a good blood supply II. Connective Tissue Characteristics ● Connects body parts ● Involved in protecting, supporting and binding other tissues ● Variations in blood supply ○ Some tissue types are well vascularized ○ Some have poor blood supply or are avascular ● Tissue includes cells and an extracellular matrix 2. Extracellular Matrix a. Made by the cells and secreted to the exterior b. Ground substance – mostly water along with adhesion proteins and polysaccharide molecules c. Fibers i. Collagen fibers—strong ii. Elastic fibers—stretch iii. Reticular fibers—fine collagen fibers which form the internal “skeleton” of some organs Connective Tissue Types a. Bone b. Cartilage c. Dense Connective tissue d. Loose Connective Tissue e. Blood Categories of Connective Tissue III. Muscle Tissue ● Function is to produce movement ○ Contract/shorten ● Three types of muscle tissue ○ Skeletal, Cardiac and Smooth MUSCLE TISSUE ● Muscle tissue can be divided functionally, is it under voluntary or involuntary control; and morphologically, striated or non-striated. ● By applying these classifications three muscle types can be described; skeletal, cardiac and smooth. ● Skeletal muscle is voluntary and striated, cardiac muscle is involuntary and striated and smooth muscle is involuntary and non-striated. TYPES OF MUSCLE TISSUE SKELETAL MUSCLE Skeletal muscle mainly attaches to the skeletal system via tendons to maintain posture and control movement for example contraction of the biceps muscle, attached to the scapula and radius, will raise the forearm. Some skeletal muscle can attach directly to other muscles or the skin, as seen in the face where numerous muscles control facial expression. CARDIAC MUSCLE Cardiac muscle tissue is found only in the heart where cardiac contractions pump blood throughout the body and maintain blood pressure. SMOOTH MUSCLE Smooth muscle tissue is found associated with numerous other organs and tissue systems such as the digestive system or respiratory system. It plays an important role in the regulation of flow in such tissues for example aiding the movement of food through the digestive system via peristalsis. B. 3 Types of Muscle Tissue ● Skeletal muscle ○ Can be controlled voluntarily ○ Cells attach to connective tissue ○ Moves bones ○ Cells are striated (striped) ○ Cells have more than one nucleus Muscle Tissue Types ● Cardiac muscle ○ Found only in the heart ○ Function is to pump blood ○ Involuntary movement ○ Cells attached to other ○ ○ cardiac muscle cells at intercalated disks Striated Cells have one nucleus Muscle Tissue Types ● Smooth muscle ○ Involuntary muscle ○ Surrounds hollow organs to move substances ○ No visible striations ○ One nucleus per cell ● NERVOUS TISSUES Nervous tissue is one of four major classes of tissues and makes up the central nervous system and the peripheral nervous system. ● Integration and communication are the two major functions of nervous tissue. ● Nervous tissue contains two categories of cells — neurons and neuroglia. ● Neurons are highly specialized nerve cells that generate and conduct nerve impulses. ● Neuroglia are supporting cells that provide physical sport, remove debris, and provide electrical insulation. IV. Nervous Tissue ● Composed of Neurons and nerve support cells ● Function is to send impulses to other areas of the body ● Makes up parts of the nervous system Nerve Tissue Neurons transmit signals ( Axons & Dendrites ) Neuroglia support cells Dendrites are responsible for responding to stimuli; they receive incoming signals towards the cell body NODE OF RANVIER facilitate the rapid conduction of nerve impulses The axon terminal is important in cell to cell communication through the neurotransmitters it releases into the synaptic cleft The cell body carries genetic information, maintains the neuron's structure, and provides energy to drive activities. Schwann cells are neuroglial cells that support neuronal function by increasing the speed of impulse propagation The axons are responsible for transmitting impulses over long distances from cell body This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells