The Human Body in Health and Illness, 4th edition Barbara Herlihy Chapter 6: Tissues and Membranes

Lesson 6-1 Objectives List the four basic types of tissues. Describe the functions of epithelial tissue. Explain how epithelial tissue is classified. Differentiate between endocrine and exocrine glands. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Types of Tissues Tissues: Groups of cells that are similar to one another in structure and function Histology: Study of tissues Four major types of tissues Epithelial Connective Nervous Muscular How does cytology differ from histology? Cytology is the study of cells and histology is the study of tissues. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Epithelial Tissue Functions Protection Absorption Filtration Secretion Transportation Epithelial tissue helps form the skin and lines most of the inner cavities, such as the mouth, respiratory tract, and reproductive tract. Epithelial tissues also transport substances. For example, epithelial tissue in the intestines absorbs water and nutrients. From what does epithelial skin tissue protect the body? It protects the body from environmental influences such as sunlight, heat, and cold and from invasion by pathogens. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Traits of Epithelial Tissue Forms continuous sheets, like floor tiles Outer surface unattached Undersurface attached to basement membrane Avascular Well-nourished, regenerates quickly The basement membrane is a thin membrane that anchors the epithelium to the underlying structure. Epithelial tissues, unlike connective tissues, have very little intercellular matrix. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Types of Epithelial Tissue Classification according to shape Squamous Cuboidal Columnar Epithelial tissue is classified according to its shape and number of layers. Squamous epithelium cells are thin, flat, and look like fish scales. Cuboidal epithelium cells are cubelike and resemble dice. Columnar epithelium cells are tall and narrow, like columns. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Layers of Epithelial Tissue Classified according to number of layers Simple epithelium Stratified epithelium One layer of cells is a simple epithelium. Two or more layers of cells form a stratified epithelium. Transitional epithelium changes from simple layer to stratified (e.g., the urinary bladder appears as simple epithelium when stretched and stratefied epithelium when unstretched). Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. .

Location of Epithelial Tissues Simple squamous epithelium is found where substances move by rapid diffusion or filtration (e.g., walls of capillaries, alveoli). Simple cuboidal epithelium, found in glands and the kidneys, secretes and transports various substances. Simple columnar epithelium lines the digestive tract and helps in the absorption of the products of digestion. Pseudostratified columnar epithelium facilitates absorption and secretion. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Glandular Epithelia Exocrine glands Endocrine glands The exocrine glands have ducts that carry the exocrine secretions outside the body. These excretions include mucus, sweat, saliva, and digestive enzymes. The endocrine glands are ductless glands and secrete hormones, such as insulin, directly into the blood. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Lesson 6-2 Objectives Describe the functions of connective, muscle, and nervous tissue. List the types of epithelial and connective tissue membranes. Differentiate between mucous and serous membranes. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Functions of Connective Tissue Connection Support Protection Fat storage Transportation Of the four types of tissue, connective tissue is the most abundant in the human body. It is widely distributed throughout the body and is found in blood, under the skin, in bone, and around many organs. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Characteristics of Connective Tissue Intercellular matrix Abundant Varies from liquid to hard Most is well vascularized. Exceptions: Tendons, ligaments, and cartilage Presence and amount of protein fibers vary. Collagen Elastin Reticular fibers (fine collagen) Each type of cell secretes a different type of intercellular matrix, which may be liquid, gel, or solid. Composed of fibrous protein and ground substance, intercellular matrix fills the spaces between cells. Protein fibers, like collagen and elastin, are present in different amounts. How do pregnancy and aging weaken connective tissue? Possible answers include stretch marks on the abdomen and sagging breasts (Cooper’s droop). Dense fibrous tissue includes tendons, ligaments, and capsules and fascia. Cartilage contributes to the structure of the skeletal system and has a cushioning effect, as in pads in the knee joints. Ask students to feel the rings in their windpipes, the midpart of the nose, and upper external ear. Point out that these structures are all cartilage. Bone, blood, and lymph are described in great detail in separate chapters. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Types of Connective Tissue Loose Areolar, adipose, reticular Dense fibrous(tendons, ligaments, capsules, and fascia) Capsules – tough sheet of dense fibrous connective tissue surrounds the kidneys and liver Fascia – sheet of tissue covering muscles, blood vessels, and nerves Why are tendons, ligaments, capsules, and fascia composed of dense fibrous tisssue and not areolar tissues? Dense fibrous tissue is stronger than areolar tissue. Areolar tissue is more suitable for acting as tissue glue. Ask students to feel cartilage in the rings in their windpipes, middle part of the nose, and upper external ear. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Types of Connective Tissue continued Cartilage Hyaline(larynx, ends of long bones at joints, the nose, and area between the breastbone and the ribs), fibrocartilage(between vertebrae and in joints of the knee), elastic(vocal cords) Bone –osseous tissue Osteoblasts mature into osteocytes. Osteoblasts secrete the intercellular matrix Blood and lymph – liquid intercellular matrix Blood’s intercellular matrix is called plasma. Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Locations of Connective Tissue Provide examples of tissues with an intercellular mix ranging from liquid to hard (solid). Blood and lymph are liquid, areolar tissue is gel, cartilage is semisolid, and bone is solid. Ask students to describe personal injuries involving torn ligaments. Points include how the injury happened, pain, and treatment. Neuroglia are cells that support and take care of the neurons. They are also called glia. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Nervous Tissue Makes up the brain, spinal cord, and nerves Two types of cells Neurons Neuroglia – cells that support and take care of the neurons Neurons carry the electrical signals that allow for rapid communication throughout the body. Neuroglia are cells that support and take care of the neurons. They are also called glia. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Muscle Tissue Composed of cells (fibers) that contract to cause movement of a body part. Three types of muscle Skeletal muscle – striated Smooth muscle – no striations Cardiac muscle – are branched and connected in complex networks. Found on in the heart. There are three types of muscle: skeletal, smooth, and cardiac. Smooth muscles move viscera and tubes such as blood vessels and ureters. Cardiac muscle is only found in the heart. What does cardiac muscle do? It is responsible for the pumping action of the heart. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Locations of Muscle Tissue Skeletal muscle is elongated and appears striated. Cardiac muscle is found only in the heart. It is elongated and striated; it forms lateral connections with other cardiac muscle fibers. This allows the electrical signal to spread very rapidly throughout the cardiac muscle. Smooth muscle is non-striated. Its shape, appearance and function are distinctive from the other two types of muscle tissue. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. .

Tissue Repair Regeneration: Replacement of tissue via mitosis Fibrosis: Replacement of injured tissue with fibrous connective tissue (scar tissue) Keloid scarring: Excessive fibrosis Damaged skeletal muscle, cardiac muscle, and nervous tissue are replaced by scar tissue. Regeneration only occurs in tissues whose cells undergo mitosis. Skeletal muscle, cardiac muscle, and nervous tissue do not undergo mitosis and must be replaced by scar tissue. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Steps in Tissue Repair Wound Clot and scab Tissue repair begins Scar tissue forms Epithelial cells multiply Scab detaches When a deep wound to the skin severs blood vessels, blood fills the wound, and then a blood clot forms, resulting in a scab. When the epithelial cells multiply, they fill the area between the scar tissue and the scab. When the epithelium is complete, the scab detaches. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Membranes Thin sheets of tissue that Classification of membranes Cover surfaces Line body cavities Surround organs Classification of membranes Epithelial Connective (described in later chapters) There are two types of membranes, epithelial and connective. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Cutaneous Membrane: Skin What types of functions does the skin perform? Responses include: protection, excretion, temperature regulation, and sensory role (touch and pain). The skin can tell a clinical story. For example, blue or cyanotic skin suggests there is not enough oxygen in the blood. Yellow skin suggests too much bilirubin in the blood and may indicate a liver or blood disease. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Connective Tissue Membranes Synovial (lines joints) Periosteum (lines bones) Perichondrium (lines cartilage) Meninges (lines central nervous system) Fascia (found throughout the body) This is from table 6-3 on page 89. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Copyright © 2007 by Saunders, an imprint of Elsevier Inc. Cutaneous Membrane The skin The outer layer is stratified squamous epithelium. The underlying layer is fibrous connective tissue. Copyright © 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Mucous Membranes Line all body cavities that open to the exterior of the body (digestive, respiratory, urinary and reproductive) Mostly stratified squamous or simple columnar epithelium. Functions: absorption and secretion Secretes mucous to keep membranes moist and lubricated. The mucous membranes contain stratified squamous epithelium or simple columnar epithelium. Mucous membranes are adapted to enable absorption, secretion, and protection. Mucus is secreted to lubricate and moisturize. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Serous Membranes Line ventral body cavities that do not open to the exterior Pleura (around lungs) Parietal and visceral Pericardium (around heart) Peritoneum (abdominal) The parietal layer is the part of the serous membrane that lines the walls of the cavity, and the visceral layer covers the outside of the organ. The intrapleural space is between the visceral and parietal pleurae. Puncture wounds of the chest can upset the negative pressure within the intrapleural space causing the lung to collapse. Why can a ruptured appendix result in peritonitis? Fecal material enters the pelvic cavity; infection ensues. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved.