Cells and tissues

CELLS – the basic unit of living things CELL THEORY – 1. Cells perform all the vital functions of a living thing. 2. Cells come from other cells. 3. Cells are the basic unit of all living things.

Basic Cell Structure NUCLEUS – control center of the cell PLASMA (CELL) MEMBRANE – barrier between the cell and its environment. CYTOPLASM – portion of the cell containing functioning organelles – substance between the nucleus and cell membrane

CELL ORGANELLES MITOCHONDRIA – produces energy – power house of the cell Ribosomes – produce proteins – located on the er

CELL ORGANELLES Endoplasmic reticulum – transport system of the cell Golgi apparatus (body) – packaging system of the cell

CELL ORGANELLES CYTOSKELETON – FRAMEWORK OF THE CELL CENTRIOLES – CONTROL CELL DIVISION OR MITOSIS

Epithelial Connective Muscle Nervous TISSUES OF THE BODY Epithelial Connective Muscle Nervous

EPITHELIAL TISSUE Tissue of the body responsible for protection, absorption, filtration, and secretion. Fit tightly together to form continuous sheets. ALWAYS have on free (unattached) surface called the apical surface. Lower surface rests on the basement membrane – connects epithelial to connective tissue below. AVASCULAR – have no blood supply of their own – depend on diffusion for nourishment

EPITHELIAL CELL ARRANGEMENT Simple – single layer of cells Stratified – multiple layers of cells

TYPES OF SIMPLE EPITHELIUM SIMPLE SQUAMOUS – found on surfaces involved in rapid diffusion – ex. Between air sacs of lungs and blood capillaries SIMPLE CUBOIDAL – common in glands; found within the kidneys and ovaries SIMPLE COLUMNAR – associated with mucous producing layers in the digestive and respiratory tract PSEUDOSTRATIFIED COLUMNAR – lines the respiratory tract – traps particles and dust

TYPES OF STRATIFIED EPITHELIUM STRATIFIED SQUAMOUS – located in areas that receive a lot of friction such as the esophagus and skin surface STRATIFIED CUBOIDAL – rare within the body – located in the mammary glands STRATIFIED COLUMNAR – rare within the body – located in salivary glands

SPECIAL EPITHELIAL TYPES TRANSITIONAL GLANDULAR Forms the inner surface of the bladder – allows for expansion Forms the secretory layers of the various glands of the body

CONNECTIVE TISSUE Tissues of the body charged with protecting, supporting, and binding things together. Most connective tissue is well vascularized – meaning it has a good blood supply. Exceptions include the tendons and ligaments. They are made of many different types of cells surrounded by a NONLIVING substance called the EXTRACELLULAR MATRIX. This matrix is composed of various types of fibers including elastic, collagen, and reticular fibers.

TYPES OF CONNECTIVE TISSUE BONE CARTILAGE Cells surrounded by a very hard matrix composed of calcium FIBROUS CONNECTIVE Form rope-like structures – tendons and ligaments BLOOD Contains cells surrounded by liquid matrix Matrix is more flexible than bone – abundant in joints of the body ADIPOSE TISSUE Tissue specialized to store fat.

SKELETAL MUSCLE TISSUE Muscle tissue that forms the muscles attached to the skeleton. VOLUNTARY Cells contain STRIATIONS which represent the high protein content of these muscle cells

CARDIAC MUSCLE TISSUE Muscle cells that comprise the muscle of the heart. INVOLUNTARY Contain STRIATIONS Contain INTERCALATED DISKS which maintain the rhythm of the heartbeat.

SMOOTH MUSCLE TISSUE Muscles the make up the muscular wall of internal organs. INVOLUNTARY NON-STRIATED Slow moving fibers – control a movement called peristalsis

NERVOUS TISSUE Comprised of cells called NEURONS All neurons receive and conduct impulses. Their cytoplasm can be drawn out into long extensions that can be as long as 3 feet or more allowing them to conduct impulses over a long distance. Supporting cells support and protect neurons – these are called glial cells.