CONNECTIVE TISSUE

Tissues n The tissues of the human body include four major types: n Epithelial n Connective n Muscle n Nervous

CONNETIVE TISSUE n CT connects, supports, protects, provides frameworks, fills spaces, stores fat, produces blood cells, protects against infection and helps repair damaged tissues. n CT cells usually have considerable intercellular material between them. n This intercellular matrix consists of fibers and a ground substance. n Comprise much of the body and are the most abundant type of tissue by weight.

Major Cell Types n There are three types of cell found in Connective Tissue. 1. Fibroblast 2. Macrophages 3. Mast Cells

Major Cell Types n Fibroblast- produce fiber by secreting protein into the matrix of CT. The most common. Large star shaped. n Macrophages-Originates as white blood cells, also very numerous in CT. Very active. Specializes in phagocytosis, functions as a scavenger cell clearing foreign particles from tissues. Contributes to the defense against infection and the body’s immunity.

Major Cell Types n Mast Cells - Large and widely distributed in CT. n Release heparin a compound that prevents blood clotting. n Releases histamine a substance that promotes some of the reactions associated with inflammation and allegories. n Located near blood vessels.

Macrophages

Mast Cells

CONNECTIVE TISSUE FIBERS n There are also 3 types of fibers found in connetctive tissue as well. 1. Collagenous fibers are composed of collagen and have great tensile strength. 2. Elastic fibers are composed of microfibrils embedded in elastic and are very elastic. 3. Reticular fibers are very fine collagenous fibers.

Collagenous Fibers n Collagenous fibers are thick threads of the protein collagen n Grouped in long parallel bundles, slightly flexible with great strength. n Important components of the body parts that hold structure together such as ligaments and tendons. n Make up a lot of CT…if you have lots of collagenous fibers you are dense CT…if you have very little you are loose CT

Collagenous Fibers

Elastic Fibers n Composed of bundles of protein called elastin n Weaker than collagenous but more elastic n Tissue that has a lot of elastic fibers usually appear yellow in color. n When stretched or deformed they will resume their original shape. n Found in body parts subject to stretching…vocal cords and air passages.

Elastic Fibers

Reticular Fibers n Very thin collagenous fibers n Highly branched and form delicate supporting networks with a variety of tissue. n Looks like a road map…easy to id.

Reticular Fibers

CATEGORIES OF CONNECTIVE TISSUE n Loose connective tissue n Adipose tissue n Reticular connective tissue n Dense connective tissue n Elastic connective tissue n Specialized connective tissue include cartilage, bone and blood.

LOOSE CONNECTIVE TISSUE n Forms delicate, thin membranes throughout the body. Cells of this tissue are mainly fibroblast. n Binds the skin to the underlying organs and fills spaces between. n Lies beneath most layers of epithelium where its many blood vessels nourish nearby epithelial cells.

LOOSE CONNECTIVE TISSUE n Loose connective tissue is also found under the epidermis (epithelium) of the skin in a region called the dermis. You can distinguish it by its vascularity and cellularity (lots of cells and blood vessels)

ADIPOSE TISSUE n Fat tissue formed when cells enlarge and become abundant. They then become adipose tissue. n Cushions joints and some organs and it stores energy. n This tissue lies beneath the skin, in spaces between muscles, around the kidneys, behind the eyeballs, in certain abdominal membranes, on the surface of the heart and around the joints.

ADIPOSE TISSUE

Reticular Connective Tissue n This tissue composed of thin collagenous fibers, in a three dimensional network. n It supports the walls of internal organs n Found in the walls of the liver, spleen, and lymphatic organs. n Again resembling a road map.

Reticular Connective Tissue

Dense Connective Tissue n Composed of many closely packed thick collagenous fibers and fine network of elastic fibers n Blood supply here is poor and this slows tissue repair. (this is why a sprain takes so long to heal) n Very strong, enabling the tissue to withstand pulling forces. Binds body parts together. n Found in Ligaments and tendons.

Elastic Connective Tissue n This tissue is mainly composed of elastic fibers…again yellow in color. n Has elastic like quality. n Found in attachments between vertebrae of spinal cord. Layers within the walls of certain hollow internal organs, including the larger arteries, some portion of the heart, and the larger airways.

Cartilage n Rigid connective tissue n Abundant and largely composed of collagenous fibers n Lacks direct blood supply and is slow to heal. n Provides supportive framework for attachments, protects underlying tissue and forms structural models for many developing bones. n Its intercelluar material is composed of fibers and a gel-like substance.(add this)

Cartilage n Major types of cartilage are hyaline cartilage, elastic cartilage,and fibrocartilage n Cartilage is at the ends of various bones,in the ear, in the larynx, and in pads between bones of the spinal column, pelvic girdle, and knees.

Hyaline Cartilage n The most common type. n Found on the ends of bones and on many joints, in the soft part of the nose, and in the supporting rings of respiratory passages. n Important in growth of most bones and repair of bones fractures n Embryo's skeleton begins as hyaline cartilage….eventually replaced by bones.

HYALINE CARTILAGE

FIBROCARTILAGE n A very tough tissue, contains many collagenous fibers. n Shock absorber for structures that are subject to pressure. n Intervertebral disks, bones of the knee, and the pelvic girdle.

FIBROCARTILAGE

ELASTIC CARTILAGE n More flexible than hyaline cartilage. n Provides the framework for the external ears and parts of the larynx.

ELASTIC CARTILAGE

Cartilage n The area in red represents ______ n The area in blue represents _____ n Red- Bone n Blue-Cartilage

BLOOD n Composed of cells suspended in a fluid intercellular matrix called plasma. n Includes red and white blood cells n White blood cells fight infection, red blood cells transport gases and has platelets involved in clotting. n Most blood cells originate from red marrow of certain bones.

BLOOD

BONE n The most rigid of CT n Hardness due to calcium phosphate and mineral salt. n Contains a great amount of collage, whose fibers are flexible and reinforce the mineral components of bone n Supports body structures, protects vital structures in the cranial and thoracic cavities and is an attachment for muscles n Bone also contains red blood cells and it stores and releases inorganic salts. n Includes bones throughout the body and middle ear.

BONE n.n.

BONE n.n.

MUSCLE TISSUE n Muscle tissue contracts, moving structures that are attached to it. n Three types 1. Skeletal 2. Smooth 3. Cardiac

SKELETAL MUSCLE TISSUE n Forms muscles that usually attach to bones and are controlled by conscious effort. (Voluntary) n Threadlike cells that have alternating light and dark cross-markings called striations. n Skeletal muscles move the head, trunk, and limbs and enable us to make facial expressions, write, talk, and sing…as well as chew, swallow and breath. n Muscle fibers contract when stimulated by nerve impulses, then immediately relax. n Located throughout the body.

SKELETAL MUSCLE TISSUE

SMOOTH MUSCLE TISSUE  Smooth because it lacks striations  Shorter than skeletal, spindle-shaped with a single, centrally located nucleus.  Usually it is involuntarily controlled.  Moves food through the digestive system, constricts blood vessels, and empties the urinary bladder.  Comprises the walls of hollow internal organs, such as stomach, intestines, urinary bladder, uterus, and blood vessels.

SMOOTH MUSCLE TISSUE

CARDIC MUSCLE TISSUE n This tissue is found only in the heart n It has striations and also joined end to end. Branched and interconnected in complex network. Each cell within a cardiac muscle fiber has a single nuclei n Cardiac muscle tissue is involuntarily controlled.. n Pumps blood through the heart chambers and into blood vessels. In fact it can continue to function without being stimulated by nerve impulses

CARDIC MUSCLE TISSUE

3 TYPES OF MUSCLE n Three Types of Human Muscle Tissue n Skeletal muscle tissue, usually found attached to the skeleton, consists of long, straight multinucleated cells with bands, or “striations.” Skeletal muscle is under voluntary, conscious control. n Smooth muscle tissue is made of spindle-shaped cells containing a single nucleus. Smooth muscle surrounds hollow internal structures, including the stomach, intestines, arteries and veins. Smooth muscle has a greater capacity than other muscle types to be stretched while retaining the ability to contract. Both smooth and cardiac muscle are considered involuntary since they generally are not under our conscious control. n Cardiac muscle tissue is found only in the heart and has several attributes in common with both skeletal and smooth muscle. It has striations or banding like skeletal muscle but is under involuntary control like smooth muscle.

Can you tell the difference??

1.) Skeletal 2.) Smooth 3.) Cardiac

Nervous Tissue n They consist of basic cells called neurons (nerve cells) which are the impulse-conducting cells of the nervous system and neuroglia cells. n They coordinate, regulate, and integrate the many body functions. n Found in the brain, spinal cord, and peripheral nerves.

Neuron