ANIMALTISSUE

THE FOUR MAJOR ANIMAL TISSUES

1. EPITHELIAL TISSUE - consists of a single layer of cells covering the surfaceof the body or severallayers lining body activitiesand organs-perform a variety offunctions, includingprotection, absorption,excretion and secretion

TWO LAYERS OF EPITHELIAL TISSUE

oSimple – single layer

oStratified – 2 or more layer

DIFFERENT KINDS OF EPITHELIAL TISSUE

SQUAMOUS EPITHELIUM

- flat and thin cells with no intercellular spaces - simple squamousepithelium allowssubstances to eithereasily diffuse through the cells or to be filtered through them

COLUMNAR EPITHELIUM- consists of cylindrical cells- It is found in the lining of the stomach and intestines, and facilitates the movement of nutrients across the epithelial barrier.

GRANDULAR EPITHELIUM- consists of modified columnar cells- found in the sweat glands and tear glands to produce secretions.

CILIATED EPITHELIUM-They are most common in the nasal and respiratory passageways, and are one of the main reasons mucus flows and carries out dead cells.

They contain“cilia” that can either help the cells move along the tissue or can help debris and waste move along the surface of the cells

CUBOIDAL EPITHELIUM- found in organs that are specialized for secretion, such as salivary glands and thyroid follicles, and those that are specialized for diffusion, such as the kidney tubules.

STRATIFIED EPITHELIUM- has epithelial cells lined up one over another.   It is found in theepidermis of the skin, the lining of the mouth cavity, and oesophagus.

PSEUDOSTRATIFIED EPITHELIUM

- Cells are columnar but tall and thin. All cells rest on the basement membrane. The unique appearance of pseudostratified epithelia occurs because the tall, thin cells intertwine.

2. CONNECTIVE TISSUE- Its function is to bind other tissues together; therefore, this tissue must be strong.

COMMON TYPES OF CONNECTIVE TISSUE

LOOSE CONNECTIVE TISSUEIt holds organs in place and attaches epithelial tissue to other underlying tissues. It also surrounds the blood vessels and nerves. Cells called fibroblasts are widely dispersed in this tissue; they are irregular branching cells that secrete strong fibrous proteins and proteoglycans as an extracellular matrix.

LOOSE CONNECTIVE TISSUE Areolar connective tissue

DENSE CONNECTIVE TISSUE- provides connection between

different tissues in the human body- it forms strong, rope-like structures

such as tendons and ligaments. Tendons attach skeletal muscles to bones; ligaments connect bones to bones at joints. Ligaments are more stretchy and contain more elastic fibres than tendons.

DENSE CONNECTIVE TISSUE

FIBROUS TISSUES

- Holds muscle cells and surrounds groups of cells that make up the nerves

- Composed of parallel bundles of collagen fibers, is found in the dermis, tendons, and ligaments

FIBROUS TISSUES

CARTILAGE TISSUE

- It is found at joints surface and rib ends. They are also present in the tracheal rings.

- Cartilage cells secrete fibrous materials that are strong but flexible.

BONE TISSUE- It functions in structural  support, protection, and mineral (calcium) storage

- three types of cells: osteoblasts, which deposit bone; osteocytes, which maintain the bone; and osteoclasts, which resorb bone.

BONE TISSUE- The functional unit of compact bone is the osteon, which is made up of concentric rings of bone called lamellae surrounding a central opening called a Haversian canal, through which nerves and blood vessels travel.

ADIPOSE TISSUE

- a loose connective tissue that fills up space between organs and tissues and provides structural and metabolic support

- Serves as the fat storage and as supporting pads for other tissues

VASCULAR TISSUE(BLOOD)- Blood is composed of erythrocytes (RBC), which distribute oxygen throughout the body; Leukocytes (WBC), which mount immune responses; and thrombocytes (platelets), which are involved in blood clotting.

- Blood has a number of functions, but primarily it transports material through the body to bring nutrients to cells and remove waste material from them.

3. MUSCULAR TISSUE- They give shape and form to the body. And also help the bones move our body.

3 TYPES:• SMOOTH MUSCLE• STRIATED MUSCLE• CARDIAC MUSCLE

SMOOTH MUSCLE- spindle shaped with only one nucleus, contract involuntarily to push food through the digestive tract and blood through blood vessels.

SMOOTH MUSCLE

STRIATED MUSCLE

- Skeletal muscle cells, long, striated, multinucleate cells under voluntary control, are responsible for the movement of skeletal muscles.

STRIATED MUSCLE

CARDIAC MUSCLE

- found only in the heart, are striated and branching (with one nucleus); they are joined by intercalated discs which allow the cells to synchronize the beating of the heart.

CARDIAC MUSCLE

4. NERVOUS TISSUE

- Conducts impulses to and from body organs via neurons

*Two major cell types: Neurons - communicate with eachother  via electrical and chemical

signals - structural unit of nervous tissue

Glial cells - support the neurons

PARTS OF NEURONSCell Body - contains the nucleus

Dendrites - tree-like fashion and serve as the main apparatus for receiving signals from other nerve cells.

- pick up the electrical impulses and pass them to the cell body. 

Axon - elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal

-carries the impulse away from the cell body.