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This Powerpoint lecture covers the most common types of tissues found in the human body, including epithelium, muscle, nervous, and connective. The basic shape and pattern of the cells that make up each tissue are shown and their typical functions are explained. Example slides from different organs in the body are used to provide a context.
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Tissues
Tissues Tissues are groups of similar cells with similar
structure that perform a similar function. Division of Labor
A. Epithelium = protect surfacesB. Muscular = ContractileC. Connective= support and hold parts together. (most common and diverse. Ex. Blood, fat)D. Nervous= irritable and conducts impulses
Epithelial Tissue Line and protect the external and
Internal body surfaces. Cells fit closely together and may
form layers. Tissue has two surfaces:
Apical surface faces the external environment.
Basal surface faces inner body tissues.
Epithelium is avascular, meaning it does not have a blood supply.
Cells regenerate quickly and easily
Epithelial Tissue Primary function is to protect against
bacterial and mechanical injury. Example: Serous fluid is secreted
whenever an area is damaged (appears swollen)
Classified by appearance into several different types.
Squamous Simple squamous cells are
single-layered, flat and irregular in shape (look like scales)
Cells are very thin to allow for substances to diffuse through them quickly.
Lining of blood vessels (capillaries), heart, lungs.
Simple Squamous Epithelia
Figure 3.18a
Stratified Squamous Epithelia
Multiple layers of cells; only the ones at the apical surface are flattened.
Rapidly dividing Provide protection in
areas of high friction (skin, esophagus)
Stratified Squamous Epithelia
Figure 3.18e
Simple Cuboidal
Single layer of cube-shaped cells.
Found in glands and the kidney.
Multiple golgi bodies within each cell.
Simple Cuboidal Epithelia
Figure 3.18b
Columnar
Rectangular-shaped cells; taller than they are wide.
Line the stomach and small intestines.
Specialized to secrete mucus (lubrication)
Simple Columnar Epithelia
Figure 3.18c
Pseudostratified Ciliated Columnar
Single layer of columnar cells.
Some cells are shorter than others, giving a double-layer appearance.
Usually contains cilia, or microscopic hairs capable of movement.
Aids in transport of material through trachea and intestines.
Help filter air in the nasal passages.
Pseudostratified Ciliated Columnar
Figure 3.18d
Connective Tissue
The most abundant and widely distributed type of tissue in the body.
Multiple functions: Holds body tissues together. Provides support to other cells and
tissues. Protection.
May be vascular or avascular.
Bone (osseus) Tissue
95% of bone is non-living calcium carbonate.
Osteoblasts- form bone Osteoclasts- break down
bone Reabsorbs and sculptures
bone. Recycle Calcium Osteoporosis= when
osteoclasts are more active than osteoblasts.
Bone (osseus) Tissue
Bone cells sit inside circular “pits” or lacunae surrounded by layers of calcium salts and collagen fibers.
Connective Tissue Types
Hyaline cartilage has a glassy blue-white appearance. Found in the larynx and joints between bones.
Connective Tissue Types
Fibrocartilage is more compressible and is found between the discs of the spinal cord.
Loose Connective
Loose connective tissues are softer and contain more cells and fewer fibers than other connective tissues.
Areolar tissue is the “cobwebby” tissue that cushions and protects body organs. Areolar tissue provides water and salts for surrounding cells. An edema is when the areolar tissue becomes fluid-filled.
Dense Connective
Dense connective tissue is primarily made of fibers of collagen protein.
This type of connective tissue is very strong and stretchable. Tendons – Attach skeletal muscles to bones. Ligaments – Attach bones to bones.
Adipose Tissue Fat
Reserve source of energy Cushioning, insulation Flotation
Reticular Tissue Network of irregular-shaped reticular cells and fibers that
serve as an internal framework for tissues that hold lots of red blood cells. Spleen Bone marrow
Blood Tissue Blood cells surrounded by plasma fluid. Red blood cells transport nutrients, waste,
oxygen, and carbon dioxide to each cell in the body.
White blood cells aid in protecting against foreign
Skeletal Muscle Tissue Multinucleate, striated, with a long cylindrical
shape. Under voluntary control. Contracts and pulls on bones and skin to
produce movements and facial expressions. Muscles do not undergo mitosis.
Exercise produces larger cells, not more cells.
Smooth Muscle
Involuntary Short fibers= slow contractions Found in the walls of hollow organs (especially
the digestive tract) No visible striations, one nucleus per cell.
Cardiac Muscle
Found only in the heart Cells are branched and form a network with other cells. Can contract independently without input from the central nervous
sytem. Cells are striated, contain one nucleus per cell, and have
intercalated disks at attachment points to other cells.
Nervous Tissue Conducts impulses to other areas of the body. Neurons are cells that send and receive
electrical and chemical stimuli. Nerve support cells provide nutrients and
other materials needed by neurons.