Cell Anatomy

Membrane Physiology

Passive and Active Transport

DNA replication

Mitosis

Protein Synthesis

Cells and Tissues Chapter 3

Cell Diversity Structure – Function Relationships!

Cells that connect body parts Fibroblast – This cell secretes cable like fibers, it has abundant rough ER and a large golgi apparatus to make and secrete the protein building blocks of these fibers.

Fibroblast

Cells that cover and line body organs : Epithelial cell – They have a hexagonal shape. This shape allows them to pack together in sheets. They also have abundant intermediate filaments which resist tearing

Epithelial Cells

Cells that move organs and body parts Skeletal and smooth muscle cells are elongated and filled with contractile filaments so they can shorten forcefully and move bones or change the size of internal organs

Smooth/Skeletal Muscle

Cells that store nutrients Fat cells have a large spherical shape due to the lipid droplet in its cytoplasm

Fat Cells

Cells that fight disease Macrophage have long pseudopods which it can extend to reach through tissue to infection sites. It also contains many lysosomes to digest the infectious microorganisms it takes up.

macrophage

Cells that gather information and control body function Nerve Cells have long projections that receive and transmit messages.

Nerve Cell

Cells of reproduction Oocytes contain many copies of all organelles for distribution to the daughter cells that arise when the cell divides. Sperm are long and streamlined with a flagellum so they are built for swimming

sperm/oocyte

Tissues As a fertilized eggs divides the millions of cells that result become specialized for specific functions, creating a division of labor in the body. Groups of cells that are similar in their structure and function are called tissues.

Tissues Epithelial Tissue Connective Tissue Muscle Tissue Nervous TIssue

EPITHELIAL TISSUE Makes up the lining, covering and glandular tissue of the body. Primary functions include protection, absorption, filtration and secretion.

Special Characteristics of Epithelium Cells fit closely together and are bound by cell junctions They have one free edge exposed to either the exterior of the body or the body cavity. (apical surface) The lower surface rests on a basement membrane- a structure-less material secreted by the cells. The cells do not have their own blood supply. They depend on diffusion from connective tissue capillaries.

Classification of Epithelium 1. Simple Epithelium one layer of cells – usual functions include absorption, secretion and filtration a.Simple Squamous Epithelium – usually forms membranes where filtration or rapid exchange of substances occurs (air sacs in the lungs – capillaries)

Classification of Epithelium 1. Simple Epithelium one layer of cells – usual functions include absorption, secretion and filtration b. Simple Cuboidal Epithelium – common in glands and ducts

Classification of Epithelium 1. Simple Epithelium one layer of cells – usual functions include absorption, secretion and filtration c. Simple Columnar Epithelium – houses goblet cells. Lines the entire length of the digestive tract.

Classification of Epithelium 2. Stratified Epithelium two or more layers of cells – primary function is to protect a. Stratified Squamous Epithelium – the most common type, usually several layers of cells. The cells at the free edge are squamous, whereas those close to the basement membrane are cuboidal or columnar. Found in areas that receive a good deal of abuse or friction.

Classification of Epithelium 2. Stratified Epithelium two or more layers of cells – primary function is to protect b. Stratified Cuboidal/ Stratified Columnar – both fairly rare in the body, mainly found in the ducts of large glands.

Classification of Epithelium 2. Stratified Epithelium two or more layers of cells – primary function is to protect c. Transitional Epithelium – highly modified stratified squamous epithelium that forms the lining of the urinary system organs. They have the ability to slide past one another and change shape allowing the organs to stretch.

Classification of Epithelium 2. Stratified Epithelium two or more layers of cells – primary function is to protect d. Glandular Epithelium - makes up glands. Glands can make and secrete products. The products are called secretions and contain protein in a aqueous solution. Endocrine glands secrete directly into the blood stream (hormones) Exocrine glands secrete into ducts which go to the epithelial surface (sweat)

CONNECTIVE TISSUE It is the most abundant and widely distributed tissue in the body. It connects body parts.

Common Characteristics of Connective Tissue Most commonly it is well vascularized, however some types have very little blood supply. Although connective tissues can be made up of many different cell types, they all have varying amounts of a non living substance called the extracellular matrix.

Extracellular Matrix Cells that make up connective tissue make extracellular matrix and secrete it to their exterior. It has two man parts 1. a ground substance (mainly water and some adhesion proteins) 2. large charged polysaccharide molecules (more polysaccharides leads to harder consistency) with different amounts and types of fibers deposited in it.

Extracellular Matrix Because you can have such a broad variety in the number of cells that the matrix is surrounding, and the rigidity of the matrix itself, connective tissue comes in a wide range structures Mostly cells with a soft matrix Very few cells with large amounts of hard matrix

Extracellular Matrix

Types of Connective Tissue All composed of cells surrounded by a matrix. The major difference reflect the number and types of fibers in the matrix Bone Cartilage Dense Connective Loose Connective Blood

Bone Bone cells sitting in cavities called lacunae. Surrounded by a very hard matrix that contains Ca salts and a large amount of collagen fibers.

Cartilage less hard and more flexible than bone 1.Hyaline Cartilage – abundant collagen fibers and a rubbery matrix – between the ribs and breastbone. (most widespread) 2.Fibrocartilage – disks between the vertebrae 3.Elastic Cartilage - ears

Dense Connective Tissue A matrix of mainly collagen fibers, with rows of fibroblasts crowded in between forming strong ropelike structures Tendons- skeletal muscle to bone Ligaments – connect bones to bones at the joints Lower layers of the skin

Loose Connective Tissue Softer tissues with more cells and fewer fibers Areolar Tissue- pliable tissue that cushions and protects the body organs. “Packs” organs together in the proper positions with a fluid, loose network of fibers Adipose Tissue – forms the subcutaneous tissue beneath the skin, insulates, and stores fuel. Reticular Tissue forms the stroma in lymphnoid organs

Blood Vascular Tissue – blood cells surrounded by a fluid matrix called plasma. Transport vehicle for the cardiovascular system.

MUSCLE TISSUE Tissues that are highly specialized to contract, or shorten 3 types

Skeletal Muscle Skeletal muscle tissue is packaged by connective tissue sheets into organs called skeletal muscles. The cells are long, cylindrical, and multinucleate. They have stripes called striations. They are involved in voluntary movement

Cardiac Muscle Only found in the heart The tissue has striations, but individual cells are branching and each only have one nucleus. The branching cells fit together at intercalated disks that contain gap junctions. These junctions allow ions to pass freely from cell to cell resulting in rapid conduction of electrical impulse across the heart.

Gap Junctions

Smooth Muscle This muscle has no striations. Cells have one nucleus and are pointed at the ends. It is found in the walls of hollow organs, stomach, bladder, blood vessels, uterus… It contracts at a slower rate in order to move substances through the organ along a specific pathway.

NERVOUS TISSUE The cells are neurons whose major functions are irritability and conductivity. Along with supporting cells to insulate, support and protect the neurons, nervous tissue makes up the brain, spinal cord, and nerves.

Tissue Injuries and Repair The restoration of homeostasis after a tissue has been injured involves two related processes…. Inflammation and Regeneration

Inflammation Immediately after an injury, the area is isolated while damaged cells, tissue components, and any dangerous microorganisms are cleaned up. Familiar symptoms of inflammation include, swelling, redness, warmth and pain.

Regeneration Second, damaged tissues are replaced or repaired. The two phases overlap, isolation establishes a framework that guides the cells responsible for reconstruction, and repairs are underway before cleanup operations have ended.

Impact, abrasion, distortion, infection, chemical irritation….. Certain stimuli kill cells, damage fibers, or injures the tissue in some way. When this happens, the chemical composition of interstitial fluid is altered. The damaged cells release prostaglandins, proteins, and K+ ions Necrosis occurs due to lysosomal enzymes.

Inflammation Tissue changes trigger the connective tissue to stimulate mast cells which in turn release a variety of chemicals

Inflammation Tissue changes trigger the connective tissue to stimulate mast cells which in turn release a variety of chemicals This stimulates changes in circulation, blood vessel dilation (redness and heat)

Inflammation Tissue changes trigger the connective tissue to stimulate mast cells which in turn release a variety of chemicals This stimulates changes in circulation, blood vessel dilation (redness and heat) Abnormal tissue conditions and mast cell chemicals stimulate sensory nerve endings (pain)

Inflammation Tissue changes trigger the connective tissue to stimulate mast cells which in turn release a variety of chemicals This stimulates changes in circulation, blood vessel dilation (redness and heat) Abnormal tissue conditions and mast cell chemicals stimulate sensory nerve endings (pain) The epithelial cells in capillaries become more permeable, allowing plasma and blood proteins diffuse into the injured area. (swelling)

With the increase in blood flow you have an increase in the supply of oxygen and nutrients to the site, and an increase in the removal of wastes. Phagocytic white blood cells assist in defense and cleanup. Both debris and bacteria are engulfed and removed.

Regeneration With cleanup well underway, fibroblasts move into the necrotic area and lay down a network of collagen fibers that stabilizes the injury site.