Download Tissues and Membranes

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Anatomy and Physiology 1
Chapter 4 Outline
Tissues and Membranes
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Tissue—group of cells with similar structure and function
o 4 major groups—epithelial, connective, muscle, nerve
Epithelial tissue (Fig 4-1, 2, 3, Table 4-1)
o Coverings (outer surface) or linings (inside surface)
o No capillaries—get nutrients from connective tissue below
o Classification—based on:
ƒ Cell type
ƒ Shape
• Squamous—flat
• Cuboidal—cube shaped
• Columnar—tall and narrow
ƒ Number of layers
• Simple—one layer
• Stratified—many layers
o Simple squamous epithelium—smooth, thin, and flat
ƒ Alveoli, capillaries—allow gas and fluid exchange
o Stratified squamous epithelium—many layers of mostly flat cells (lower cells are rounded)
ƒ Mitosis occurs in the lower cells
ƒ Keratinizing epithelium
• Epidermis
ƒ Nonkeratinizing
• Mucous membranes
• Oral cavity, esophagus, vagina, etc
o Transitional epithelium—stratified epithelium with varied shapes of layers
ƒ Urinary bladder—cells flatten as bladder fills
o Simple cuboidal epithelium—single layer cube-shaped
ƒ Secretion and absorption
ƒ Glandular epithelium—secretion
• Thyroid, saliva glands
ƒ Reabsorption in kidney tubules (microvilli)
o Simple columnar epithelium—single layer taller than they are wide
ƒ Secretion and absorption
• Stomach
o secretes gastric juices (HCl and pepsin), mucus
• Small intestine
o Secretes digestive enzymes, mucus (goblet cells—unicellular gland)
o Absorption via Microvilli
o Ciliated epithelium—columnar cells with cilia
ƒ Nasal cavities, larynx, trachea, bronchials
• Sweep mucus trapped debris
ƒ Fallopian tubes
• Sweep egg
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Glands—cells or organs that secrete something
o Unicellular or multicellular
o Unicellular—one cell
ƒ Goblet cells—respiratory and digestive tracts
• Secrete mucus
o Multicellular—similar or dissimilar cells that combine secretions
ƒ 2 types—Exocrine and endocrine
ƒ Exocrine—have ducts
• Salivary, sweat, gastric, pancreas (both endo & exo)—digestive enzymes into
duodenum
ƒ Endocrine—ductless
• Secrete directly into the blood or interstitial fluid
• Secrete hormones
• Thyroid, adrenals, pituitary, pancreas—insulin and glucagons into blood
Connective tissue (Table 4-2)—blood, areolar (loose), adipose, fibrous, elastic, bone, cartilage
o Matrix and cells
o Matrix—structural network or solution of nonliving intercellular material
ƒ Plasma, calcium salts, collagen, etc.
o Blood (Fig 4-4 A)
ƒ Cells—WBCs, RBCs, platelets
ƒ Matrix—plasma
ƒ Hemopoietic tissue—blood forming
• In red bone marrow and lymphatics (spleen and lymph nodes)
• Marrow—RBCs, 5 types of WBCs, and platelets
• Lymphatics—2 types of WBCs
• RBCs—carry O2 on hemoglobin
• WBCs—destroy pathogens and provide immunity
• Platelets—clotting
o Areolar (also called loose) (Fig 4-4 B)
ƒ Cells—Fibroblasts—Produce protein fibers
ƒ Matrix—2 types of fibers
• collagen (strong, inelastic)
• elastin (elastic)
ƒ Found beneath all epithelial tissue that have openings to the environment and the
dermis of the skin
ƒ Contain WBCs to fight infection in this sub-surface layer
o Adipose (Fig 4-4 C)
ƒ Cells—adipocytes—store fat
ƒ Matrix (very small amount)—fluid and collagen fibers
ƒ Mostly subcutaneous in areolar connective tissue
ƒ Also around kidneys and eyes for protection
o Fibrous (Fig 4-5 A)
ƒ Cells—fibroblasts
ƒ Matrix—collagen
ƒ Outer walls of arteries (high pressure), tendons, ligaments—parallel fibers
• Poor blood supply—slow healing
ƒ Dermis and fascia—randomly arranged
• Good blood supply
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o Elastic
ƒ Cells—fibroblasts
ƒ Matrix—mostly elastin
ƒ In walls of large arteries—allows them to stretch and recoil
ƒ In alveoli—stretch during inhalation then contract to push air out
ƒ Some ligaments
o Bone (Fig 4-5 C)
ƒ Cells—osteocytes
ƒ Matrix—calcium salts and collagen
ƒ Arranged into haversian systems
ƒ Skeletal support, organ protection, red bone marrow in femur head, pelvis,
sternum—produce blood cells
ƒ Good blood supply—fast healing
o Cartilage (Fig 4-5 B)
ƒ Cells—chondrocytes
ƒ Matrix—protein
ƒ Joint surfaces—decreases friction (smooth)
ƒ External ear, nose, trachea—structural support
ƒ IVDs—shock absorption, allows movement
ƒ No capillaries—nutrients by diffusion—slow healing
Muscle tissue (Table 4-3)—skeletal, smooth, cardiac
o Skeletal (aka striated or voluntary)
ƒ Cells (Fig 4-6 A)
• Cylindrical
• Several nuclei in each
• Striated (striped)—contractile proteins
ƒ Attach to bone to move the skeleton
ƒ Each cell has its own motor nerve ending—can be controlled voluntarily
ƒ Produce heat to maintain body temperature
ƒ Review of names
• Skeletal—location
• Striated—appearance
• Voluntary—function
o Smooth (aka involuntary or visceral)
ƒ Cells (Fig 4-6 B)
• Tapered ends
• Single nuclei
• No striations
ƒ In many visceral organs
ƒ Involuntary—work on their own
• GI tract—peristalsis
• Blood vessels—dilate to maintain blood pressure
• Iris—constricts or dilates the pupil
ƒ Review of names
• Visceral—location
• Smooth—appearance
• Involuntary—function
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o Cardiac
ƒ Cells (Fig 4-6 C)
• Branched
• Single nucleus
• Small striations
ƒ Forms the myocardium (heart muscle)—the walls of the chambers of the heart
• Pumps blood
ƒ Electrical impulses produced in the heart cause cells to contract in unison
Nervous tissue (Table 4-4)
o Neurons—generate and carry electrochemical
impulses
o Has a direct role in almost every body function
o 2 structural divisions
ƒ CNS—brain and spinal cord
• Neurons and neuroglial cells
ƒ PNS—peripheral nerves
• Neurons and Schwann cells
(produce myelin sheath)
o Neuron structure
ƒ Cell body—contains organelles
ƒ Axons—process that carries impulses
away from the cell body
• Only one
ƒ Dendrites—processes that carry
impulses toward the cell body
• May have several
o Electrochemical impulses
ƒ Electrical impulses travel along the cell
membrane
ƒ Converted to chemical impulses
(neurotransmitters) at the synapse
(place where axon of one neuron meets
the dendrite of another)
Membranes—epithelial (serous & mucous) and connective tissue membranes
o Epithelial—serous and mucous (Fig 4-8)
ƒ Secrete fluids
ƒ Serous membranes—simple squamous epithelium that line closed body cavities and
cover organs in these cavities
• Secrete serous fluid—prevents friction
• Types of serous membranes
o Parietal pleura—lines thoracic cavity
o Visceral pleura—covers lungs
o Parietal pericardium—lines the fibrous pericardium
o Visceral pericardium (epicardium)—covers the heart
o Peritoneum—lines abdominal cavity
o Visceral peritoneum (mesentery)—covers abdominal organs
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Mucous membranes—line body tracts that have openings to the outside
• Respiratory, digestive, urinary, and reproductive tracts
• Secrete mucus—keeps cells wet, lubricates, traps dust and bacteria
• Epithelium (mucosa) varies
o Esophagus and vagina—stratified squamous
o Trachea—ciliated
o Stomach—columnar
o Connective tissue membranes—made of connective tissue
ƒ Covered in Organ Systems (Table 4-5)
ƒ Superficial fascia—between skin and muscles
ƒ Periosteum—covers bone, anchors tendons and ligaments to bone
ƒ Perichondrium—covers cartilage
ƒ Synovial—lines synovial joint cavities, secretes synovial fluid
ƒ Deep fascia—covers skeletal muscles, anchors tendons to muscle
ƒ Meninges—cover the brain and spinal cord
ƒ Fibrous pericardium—forms a sac around the heart, lined by parietal pericardium
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