chapter 3

group of similar cells with a common embryological origin that do specialized tasks

• Epithelial
• Connective
• Muscle
• Nervous

• Covers body surfaces
• lines hollow organs, body cavities, & ducts; forms glands

points of contact between adjacent plasma membranes

Form fluid tight seals between cells

Fasten cells to one another or to the extracellular material

Permit electrical or chemical signals to pass from cell to cell

• gap
• anchoring
• tight

• 1. Apical surface is the exposed surface
• 2. Basal surface is attached to the basement membrane, which is composed of a: Basal lamina which is formed from secretions from the epithelium & the reticular lamina which is formed from connective tissue secretions
• 3. avascular (no blood vessels)
• 4. innervated (has nervous tissue)
• 5. high mitotic rate

• simple
• stratisfied
• pseudostratisfied

single layer of cells

• squamous
• cuboidal
• columnar

multiple layers of cells, but classified by the top layer

• squamous
• cuboidal
• columnar
• transitional

single layer of cells, but due to the placement of the nuclei, it looks like its stratisfied

• exocrine glands
• endocrine glands

ducted glands leading to an epithelial surface

• holocrine gland
• merocrine gland
• apocrine gland

Epithelial cells lining the gland accumulate the secretory product inside, die, & are secreted as a whole unit - sebaceous(oil) gland of the skin

Exocytotic release of secretory product- salivary & most sweat

Release via the pinching off(budding) of the apical surface of the epithelial cell

ductless glands; the secretory products are secreted into the extracellular matrix & diffuse into the blood stream

• 1. Made up of cells, ground substance, & fibers
• 2. innervated
• 3. vascularized
• 4. The matrix is composed of the ground substance (glue) + fibers; matrix can vary in its consistency - fluid, gelatinous, calcified
• 5. The matrix is derived from secretions from both the CT cells & adjacent cells

• 1. Fibroblasts- matrix secreting cells for loose & dense CT
• 2. Osteoblasts- matrix secreting cells in bone
• 3. Chondroblasts- matrix secreting cells in cartilage
• 4. Adipocytes- fat cells for insulation & energy
• 5. Macrophages- phagocytes
• 6. Plasma cells - antibody production
• 7. Blood cells- red & white

• 1. Hyaluronic acid - binds cells together, joint lubrication
• 2. Chondroitin sulfate & keratan sulfate - support & adhesiveness in cartilage, bone, blood vessels
• 3. Dermatan sulfate - support & adhesiveness in skin

• 1. Collagen fibers - collagen protein; typically occur in bundles; bone, cartilage, tendons, & ligaments
• 2. Elastic fibers - elastin protein; freely branching; skin, blood vessels
• 3. Reticular fibers - collagen + glycoproteins; branching, supporting network of many organs

EMBRYONIC CT

composed of mesenchymal cells & reticular fibers; forms all other kinds of CT

• mesenchyme
• mucous CT

fibroblasts & collagen fibers; found in the fetus

• Areolar CT
• Adipose
• Reticular CT

composed of a variety of cell types along with all types of fibers; it provides strength, elasticity, & support

composed of adipocytes; it provides insulation, energy, support, & protection; subcutaneous layer of the skin, yellow marrow of long bones

composed of reticular cells & reticular fibers; forms the stroma(framework) of organs, binds smooth muscle cells

• Dense regular CT
• dense irregular CT
• elastic CT

• composed of fibroblasts & bundles of collagen fibers;
• provides strong attachments between various structures;
• tendons (muscle to bone), ligaments (bone to bone)

composed of fibroblasts & randomly arranged collagen fibers; it provides strength; found in membrane capsules around organs

composed of fibroblasts & elastic fibers; allows stretching of organs

• 1. Composed of a dense network of collagen & elastic fibers embedded in chondroitin sulfate
• 2. Collagen gives cartilage its strength
• 3. Chondroitin sulfate gives cartilage its resilience
• 4. Cells of mature cartilage are called chondrocytes & they are located in spaces called lacunae
• 5. Surface of most cartilage is surrounded by the perichondrium, a layer of dense, irregular CT
• 6. Cartilage has no blood vessels or nerves except for those in the perichondrium

• hyaline cartilage
• fibrocartilage
• elastic cartilage

composed of thin collagen fibers that are not visible and the standard chondrocytes in lacunae

composed of bundles collagen fibers that are visible and the standard chondrocytes in lacunae

composed of elastic fibers that are visible and the standard chondrocytes in lacunae

• 1. Bone tissue is classified as either compact or spongy
• 2. The basic unit of compact bone is the osteon or Haversian system
• 3. It is comprised of a central (Haversian) canal that contains blood vessels & nerves
• 4. Surrounding the canal are lamellae, which are concentric rings of calcified matrix which are secreted by osteoblasts which form the bone.
• 5. The osteoblasts mature into osteocytes which are now embedded between the lamellae in spaces called lacunae, which are analogous to cartilage lacunae
• 6. The lacunae are connected by channels called canaliculi, which allow nutrients & wastes to be transported into & out of the bone.
• 7. Spongy bone do not possess osteons, but trabeculae, which are columns of bone containing lamellae, ostecocytes, lacunae, & canaliculi - no central canal
• 8. Bone provides support, protection, movement, & houses blood forming tissue

• 1. Blood is a CT with a liquid matrix called plasma, which is
• composed of water & dissolved solutes
• 2. Erythrocytes are red blood cells necessary for the transport of oxygen & carbon dioxide
• 3. Leukocytes are white blood cells which provide immunity
• 4. Platelets function in blood clotting

• 1. Epithelial membranes are composed of an epithelial layer & an underlying layer of CT
• 2. The principal epithelial membranes are mucous & serous
• 3. Mucous membranes (mucosa) line body cavities that are exposed to the exterior (examples are digestive and respiratory tracts), providing a barrier to infection, lubrication, and even enzymes for chemical reactions
• 4. Serous membranes (serosa) line body cavities that are not exposed to the exterior & cover the organs within the cavities
• 5. The mesothelium of the serosa secretes serous fluid, providing lubrication so that the organs can easily glide against one another.
• 6. The serosa can be divided into the parietal layer which lines the cavity, the visceral layer which covers the organs

• 1. Attached to bones by tendons
• 2. They are striated- alternating light & dark bands of structures within the cells
• 3. It is voluntary, since its contractions are under conscious control

• 1. Forms the bulk of the heart wall
• 2. They are striated - alternating light & dark bands of structures within the cells
• 3. It is involuntary, since its contractions are not under conscious control
• 4. Cardiac muscle fibers are connected to one another at their ends by thickenings of the plasma membrane, called intercalated discs
• 5. The intercalated discs contain both adhering & gap junctions
• 6. The gap junctions allow electrical impulses to move rapidly through the heart, providing a smooth continuous contraction that is necessary for pumping blood

• 1. It is located in the walls of hollow organs (blood vessels, digestive tract)
• 2. They are not striated, involuntary, & some possess gap junctions
• 3. They provide for involuntary movement of material & mixing

• 1. Nervous tissue is composed of two cell types: neurons & neuroglia
• 2. Neurons are the structural & functional units of the nervous system. They respond to stimuli & control the body to react to that stimuli.
• 3. Structurally the neuron is composed of a cell body, dendrites (specialized structures that receive & conduct nerve impulses (information) to the cell body, & an axon (which conveys the information to the next cell)

• 4.
• Neuroglia are support cells that maintain proper neuron functions