Compartmentation: Cells and Tissues 3

Three Major Body Cavities The body is divided into various cavities but not all compartments have walls or are completely enclosed Figure 3-1

Lumens of Hollow Organs Hollow organs- contain a space filled with something other than the organ’s tissue. Heart Lungs Blood vessels Intestines Lumen – interior of a hollow organ Fluid-filled interior Not the internal environment- as is in the GI tract

Functional Compartments Extracellular fluid- found outside of organ tissue Plasma-fluid of blood Interstitial fluid- fluid between blood vessels and tissue cells Intracellular fluid-fluid inside tissue cells

Body Fluid Compartments Figure 3-2

Cell Membrane: Overview Membranes in the body may be macroscopic or microscopic and serve different functions Figure 3-3

Cell Membrane: Function Physical barrier- separates intracellular and extracellular fluid Gateway for exchange- controls what enters and leaves the cell Communication- surface proteins respond and recognize other molecules which can change cell activity Cell structure- cell shape is maintained by cytoskeletal proteins attached to membrane proteins. Membrane proteins also form cell junctions Phospholipid bilayer- composed of mostly lipids and proteins, it’s hydrophobic and hydrophilic regions assist in controlling transport.

Cell Membrane: Structure The fluid mosaic model of a biological membrane Figure 3-4

Cell Membrane: Composition Lipids Phospolipids – a glycerol molecule with one phosphate and two fatty acid tails- makes up a large percentage of the membrane. Cholesterols- imbedded in the bilayer it stabilizes the membrane and reduces it’s freezing point. Proteins Integral – transmembrane protein, serves as a channel Peripheral – side proteins that may be enzyme of cytoskeleton anchors Lipid-anchored – associate with sphingolipids to form lipid rafts that may attract other proteins or enzymes Carbohydrates Glycolipids- carbohydrates and fatty acids Glycoprotiens-carbohydrates and proteins

Cell Membrane: Formation Phospholipid molecules are composed of two fatty acid chains, one glycerol molecule, & one phosphate group Figure 3-5a

Cell Membrane: Formation Figure 3-5b

Cell Membrane: Proteins The three types of membrane proteins: integral, peripheral, and lipid-anchored Figure 3-6

Cell Membrane Concept Map of cell membrane components Figure 3-9

The cell membrane covers cells of various sizes, shapes, and functions Figure 3-10

Cell Compartments Cytoplasm- The space between the plasma membrane and the nucleus Cytosol - the jelly like substance that suspends the organelles Inclusions - a non-membranous organelle or insoluble particles Organelles - cell structures with specific function- “small organs” Nucleus- contains the genetic information for the cell as chromatin, the nucleolus, and nucleoplasm.

Cell Compartments A map for the study of cell structure Figure 3-11

Organelle “Factory” and summary chart See board drawing and table on board Review on your own the functions and structures of the following cell organelles (see fig 3:12): Inclusions (3-types) Centrioles, Cillia, & Flagella Cytoplasmic protein fibers (3 sizes) Cytoskeleton Mitochondria Smooth/Rough Endoplasmic Reticulum Cytoplasmic Vesicles Nucleus

Primary Tissue Types Epithelial- major functions: are protection, exchange, and lining cavities. Connective- major functions are: support, storage, communication, immunity. Muscle- major functions are: posture, movement, heat production, support and protection. Nerve- major function is communication and control, information processing.

Epithelial Tissue: Structure Basal lamina Basement membrane

Epithelial Tissue: Function Exchange – quick movement of molecules Transport – move from one side to another and process Ciliated – move substances in the extracellular matrix Protective – multiple layers, quickly regenerates Secretory – produces substances secreted into the extracellular matrix or outside the body.

Exchange Epithelia Single cell layer of flat cells that allow molecules to cross through at different rates, increase surface area with microvilli. Rapid transport - Oxygen - Carbon dioxide - Ions and fluids - Capillaries and lung alveoli -

Transporting Epithelia single layer or cuboidal or columnar cells, take in a molecule from a lumen and transport it into the blood stream. Exchange of ions and nutrients - Tight junctions - Intestine and kidney -

Ciliated and Protective Epithelia apical cilia allow more the movement of substance on the surface of the cell, like the ovum or mucus Ciliated epithelium - Trachea - Sweep mucous out - Protective epithelium - multiple layers and in skin, serve for protection. Cell have a high regenerative ability. Skin - Prevent exchange -

Secretory Epithelia contain goblet cells and cells that form the different endocrine or exocrine glands in the body Exocrine tissues Mucous glands Goblet cells Secreted externally via ducts Endocrine tissues Hormones Secreted to ECF and blood

Secretory Epithelia Development of endocrine and exocrine glands from epithelium Figure 3-28 (1 of 3)

Connective Tissues: Structure Support and barriers – strong high collagen content allow to withstand forces Ground substance – varies in amount of water and changes the consistency of the type of connecitve tissue Cells – have a wide variety of functions Fixed – imbedded in a dense ground substance Mobile – blood cells surrounded by a fluid ground substance such as plasma, are able to enter or leave the blood stream.

Connective Tissues: Structure Fibers and their functions- found in the ground substance, the different ratios of each give each type of connective tissue their unique characteristics. Fibroblast cells - produce the fibers and ground substance Collagen – has a stronger tensile strength than steel, there are 12 variations, is most abundant in the body. Elastin – gives elasticity to tissues Fibrillin – combines with elastin to give support to elastic organs. Fibronectin – stick to extracellular matrix of cells and helps in forming blood clots Reticular fibers- form a network of supportive fibers for cells composed of free cells as in bone marrow, spleen, and lymphnodes

Connective Tissues: Types

Cells and Fibers of Loose Connective Tissue Figure 3-29 (1 of 2)

Various Connective Tissue Types Strength or flexibility Tendons and ligaments Collagen dominates Adipose connective tissue White Single droplet Brown Multiple droplets Blood Plasma matrix Free blood cells Cartilage Light and flexible Trachea and ears Bone Calcified Rigid

Muscle Tissues Contractile Signal conduction Types Force and movement Cardiac Smooth Skeletal

Nervous Tissues Neurons send signals Glial cells support Excitable Electrical Chemical Glial cells support

Cell Death and Replacement Apoptosis- cell death not caused by injury or other external reasons Normal cell replacement – during body formation, or in normal body function cells reach a life limit and die Programmed cell death - induced by the cell without disturbing adjacent cells; “cell suicide” Stem cells – undifferentiated cells that can become any cell needed in the body, totipotent, puripotent, and mulitpotent Role in cell replacement – certain tissues have multipotent stem cells that can replace cells Research uses and potential – need to find a good source of stem cells, face many ethical issues

Organs Groups of tissues with related function – each contains the four types of tissues in various ratios Epidermal tissue (skin) - Multiple cell layers – epidermis, dermis, hypodermis Multiple tissue types – epitheial, connective, muscular, nervous Multiple functions – protection, metabolism, temperature regulation, water proofing, blood storage, insulation, excretion, sensory organ

UN 3-1 - Overview

Integument System Functions Protection Insulation Water proofing Temperature regulation Excretion Cutaneous Sensory organ Metabolism Blood reservoir