Chapter 2 Chemistry Of Life/ The tissues Flashcards
Cell composition
- contain cytoplasm (a substance that exists only in cells)
- each cell in the body is surrounded by a thin membrane, the plasma membrane (this membrane separates the cell contents from the salty solutions (interstitial fluid) that bathes every cell in the body)
- specialized structures, organelles are contained within the cytoplasm of each cell
- nucleus is also inside the cell
The three main parts of a cell are
- plasma membrane
- cytoplasm
- nucleus
Plasma membrane
- encloses the cytoplasm and forms the outer boundary of the cell
- two layers of phosphate- containing fat molecules called phospholipids form a fluid framework for the plasma membrane
- cholesterol helps stabilize the phospholipid molecules to prevent breakage of the plasma membrane
- protein molecules dot the surfaces of the membrane
- serves as a well guarded gateway between the fluid inside the cell and the fluid around it
- certain substances can move through the membrane by way of transporter channels and carriers, but other substances are barred from entry
- certain molecules bind to certain receptor proteins
- identifies a cell as being part of one particular individual
Passive transport processes
Going down a concentration gradient; substances move from a region of high concentration to a region of low concentration until they reach equal proportions on both sides of the membrane
1. Diffusion
▪️osmosis
2. filtration
Diffusion
Movement of particles through a membrane from an area of high concentration to an area of low concentration; that is, down the concentration gradient
- ex: movement of carbon dioxide out of all cells; movement of sodium ions into nerve cells as they conduct an impulse
Osmosis
Diffusion of water through a selectively permeable membrane in the presence of at least one impermeant solute
- ex: diffusion of water molecules into and out of cells to correct imbalances in water concentration
Filtration
Movement of water and small solute particles, but not larger particles, through a filtration membrane; movement occurs from area of high pressure to area of low pressure
- ex: in the kidney, water and small solute move from blood vessels but blood proteins and blood cells do not, thus beginning the formation of urine
Active transport processes
The uphill movement of a substance through a living cell membrane, up a concentration gradient (from a lower to a higher concentration)
▪️energy required for this movement is obtained from ATP
-ion pump
-phagocytosis
-pinocytosis
Ion pump
Movement of solute particles from an area of low concentration to an area of high concentration (up the concentration gradient) by means of a carrier protein structure
-ex: in muscle cells, pumping of nearly all calcium ions to special compartments-or out of the cell
Phagocytosis
Movement of a cell or other large particle into a cell by trapping it in a section of plasma membrane that pinches off inside the cell
-ex: trapping of bacterial cells by phagocytic white blood cells
Pinocytosis
Movement of fluid and dissolved molecules into a cell by trapping them in a section of plasma membrane that pinches off inside the cell
-ex: trapping of large protein molecules by some body cells
Body fluid compartments
Total body fluid can be subdivided into two major fluid compartments
- Extracellular fluid compartments
- Intracellular fluid compartments
Extracellular fluid (ECF)
- consists mainly of the liquid part of whole blood called the plasma, found in the blood vessels, and the interstitial fluid (IF) that surrounds the cells
- ex: lymph, cerebrospinal fluid, fluids of eyeball, synovial joint fluids
Intracellular fluid (ICF)
- the largest volume of body fluid but far
- located inside all of the cells of the body
Hypertrophy
Increase in cell size
Atrophy
Decrease in cell size
Hyperplasia
Increase in cell reproduction
Anaplasia
Production of abnormal, undifferentiated cells
The four main kinds of tissues that compose the body’s many organs include
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
Epithelial tissue
-covers the body and many of its parts
-cells are packed close together with little or no interstitial fluid or other material between them, they form continuous sheets that contain no blood vessels
shape of cells:
-squamous (flat and scalelike)
-cuboidal (cube shaped)
-columnar (more tall than wide)
-transitional (varying shapes that can stretch)
Arrangement of cells:
-simple (a single layer of cells of the same shape)
-stratified (many layers of cells)
Simple squamous epithelium
- single layer of flattened cells
- located in alveoli of lungs, lining of blood and lymphatic vessels
- diffusion, filtration, and osmosis
Stratified squamous
- many layers; outermost layer(s) is flattened cells
- located: surface of lining of mouth and esophagus, surface of skin (epidermis)
- protection
Simple columnar
- single layer of tall, narrow cells
- located: surface layer of lining of stomach, intestines, parts of respiratory tract
- protection; secretion; transport (absorption)
Stratified transitional
- many layers of varying shapes, capable of stretching
- located: urinary bladder
- protection
Pseudostratified
- single layer of tall cells that wedge together to appear as if there are two or more layers
- located: lining of portions of the respiratory tract, lining of uterine (fallopian) tubes
- protection
Simple cuboidal
- single layer of cells that are as tall as they are wide
- located: glands; kidney tubules
- secretion, absorption
Connective tissue
- most abundant and widely distributed tissue in the body
- relatively few cells embedded in the matrix of most types of connective tissue, varying numbers and kinds of fibers are also present
- varies in strength, elasticity, blood supply, and ability to heal
1. Areolar connective tissue
2. Adipose (fat) tissue
3. Fibrous connective tissue
4. Bone
5. Cartilage
6. Blood
7. Hematopoietic tissue
Areolar (loose fibrous) connective tissue
- most widely distributed
- loose arrangement of collagen fibers, elastic fibers, and cells
- located: area between other tissues and organs
- connection
Adipose (fat) connective tissue
- cells contain large fat vesicles
- located: area under the skin, padding at various points
- protection; insulation; support; nutrient reserve
Reticular connective tissue
- netlike arrangement of thin, delicate reticular fibres
- located: red bone marrow; lymph nodes; spleen
- supports soft tissues; filtration
Dense fibrous connective tissue
- dense arrangement of collagen fiber bundles
- located: tendons; ligaments; fascia; scar tissue
- flexible but strong connection
Bone connective tissue
- hard, calcified matrix arranged in osteons
- located: skeleton
- support; protection
Cartilage connective tissue
- hard but flexible matrix with embedded chondrocytes
- located: part of the nasal septum; area covering articular surfaces of bones; larynx; rings in trachea and bronchi; disks between vertebrae, external ear
- firm but flexible support, withstand pressure
Blood
- liquid matrix with flowing red and white cells
- located: blood vessels
- transportation
Hematopoietic connective tissue
- liquid matrix with dense arrangement of blood cell- producing cells (often supported by reticular tissue)
- located: red bone marrow; lymph nodes, thymus, spleen
- blood cell formation
Chondrocytes
Cartilage cells
Muscle tissue
- have a higher degree of contractility (ability to shorten or contract) than any other tissue cells
- there are three kinds of muscle tissue:
1. Skeletal muscle tissue
2. Cardiac muscle tissue
3. Smooth muscle tissue
Skeletal (striated voluntary) muscle tissue
- long, threadlike cells with multiple nuclei and striations
- located: muscles that attach to bones, eyeball muscles, upper third of esophagus
- maintenance of posture; movement of bones, eye movements, involved in first part of swallowing