Body Tissues and Membranes Chapter 4

Lesson 1 Body Tissues

Tissue  Specialized cells of similar structures that perform common functions  1. Epithelial – covers and lines body surfaces and organs  2. Connective – binds and supports body parts  3. Muscular – contracts for voluntary and involuntary movements  4. Nervous – responds to stimuli

Epithelial Tissue  Tightly packed  External:  Protects from drying out  Protects from injury  Protects from infection  Internal: protection and special jobs  Lines respiratory tract  Sweeps out toxins with cilia

Epithelial Tissue  Simple squamous – single layer of flattened cells, found in areas where simple diffusion occurs  Stratified squamous – many cell layers, plays a protective role  Simple cuboidal – single layer of cube-shaped cells attached to a basement membrane, found in glands, also covers the ovaries and lines kidney tubules  Stratified cuboidal – found lining the larger ducts of glands, has two layers

Epithelial Cells  Simple columnar – cells that are longer than they are wide, modified to perform particular functions, known for lining digestive organs  Pseudostratified columnar – appears to be layer, but true layers don’t exist, each cell touches basement membrane, tapered and narrow at one end  Transitional – changes is response to tension, found in lining of urinary bladder, ureters, part of urethra

Connective Tissue Functions:  Binds structures  Support  Protection  Fill space  Produce blood cells  Store fat Classifications:  Fibrous  Cartilage  Bone  Blood

Connective Tissue  Fibrous  Loose – lies between other tissues or between organs  Ex. Adipose tissue (store fat)  Dense – contain thick bundles of collagen fibers  Ex. Tendons, ligaments

Connective Tissue  Cartilage – solid yet flexible, lack direct blood supply, heals very slowly  Three types  Hyaline – most common, strong and durable, yet flexible  found in nose, end of long bones and ribs, supporting rings of trachea  Elastic – more flexible than hyaline  Found in framework of outer ear  Fibrocartilage – strong collagen fibers, absorbs shock and reduces friction between joints

Connective Tissue  Bone – most rigid connective tissue  Compact bone – outer portion of long bone, many cylindrical-shaped units called osteons  Spongy bone – numerous bony bars and plates, lighter, but designed for strength

Connective Tissue  Blood – composed of formed elements suspended in a liquid matrix called plasma  Types of formed elements  Red blood cells – carry oxygen  White blood cells – aid in fighting infection  Platelets – important for initiating blood clotting

Nervous Tissue Location:  Brain  Spinal cord  Central nervous system  Peripheral nervous system Functions:  Detect and respond to stimuli  Send messages through neurons

Neuron

Neuroglia  Support and nourish neurons  Make up half of the brain  Outnumber neurons 9:1

Brain Neuroglia  Microglia: engulf bacteria and cell debris  Astrocytes: nutrients, hormone (growth factor) which may cure parkinsons  Oligodendrocytes: form myelin  Ependymal cells: line hollow cavities of the brain

Lesson 2 Examining Muscle Tissue

Muscular Tissue  Contractile  Muscle fibers: proteins that slide across each other to contract/relax and create movement  Actin – Thin filament  Myosin – Thick filament

Skeletal Muscle Functions:  Voluntary  Attaches tendons and ligaments to bone  Muscle contractions = shorten  Muscle relaxation = lengthen Characteristics:  Striated (striped)  Long  Cylindrical shaped  Multinucleated

Smooth Muscle Functions:  Involuntary  Found in hollow organs Ex: stomach, esophagus, bladder, intestines Characteristics:  Non-striated  Spindle shaped  Multinucleated

Cardiac Muscle Functions:  Involuntary  Contracts to pump blood within the heart and blood vessels Characteristics:  Striated  Branched, look like one large muscle  Single nuclei

Extracellular Junction  Tight Junction: impermeable barrier (epithelial tissue)  Stomach, intestine, kidney, bladder  Gap Junction: allows small molecules  Heart for synchronization  Adhesion Junction: don’t touch, held together by filaments  Cervix to allow opening without tearing during childbirth

Content Check Match each type of extracellular junction to its function: 1.Adhesion junction 2.Tight junction 3.Gap junction a)Allows ions and small molecules to pass between cells b)Prevent adjacent cells from tearing apart c)Forms an impermeable barrier

Lesson 3 Glands/Cancer

Glands Cells which produce a product Exocrine  Release products outside of the body Ex: sweat, mammary Endocrine  Release products internally  Promote homeostasis  Made up of epithelial tissues Ex: thyroid, adrenal, testes, ovaries, pancreas, parathyroid

Membranes Functions:  Line internal spaces of organs and tubes that open to the outside  Line body cavities Types:  Mucous  Serous  Synovial  Meninges  Cutaneous

Mucous Membranes Functions:  Line interior walls of organs that open to the outside of the body  Protect from bacteria and viruses Examples:  Digestive  Respiratory  Excretory  reproductive

Serous Membranes Functions:  Line cavities  Cover organs  Epithelial tissue Examples:  Pleurae: line lungs  Pericardium: covers heart  Peritoneum: lines abdomen

Synovial Membranes Functions:  Line free moving joint cavities Examples:  Ball and socket  Hinge  Pivot  Gliding  Saddle

Meninges Cutaneous  Protect brain and spinal cord  Skin  Outer covering of the body  Keratin  Epithelial tissue

Content Check Match each type of membrane to its function: 1.Synovial membrane 2.Cutaneous membrane 3.Mucous membrane a)Forms outer covering of the body b)Lines walls of organs that open to the outside of the body c)Lines the interior of a joint capsule