Cellular Membrane Chapter 3 in textbook

Unit 2 Goals 2.1 Describe the structure and function of all organelles of an animal cell including the plasma membrane 2.2 Differentiate between isotonic, hypotonic and hypertonic solutions and how cells respond to each 2.3 Explain the mechanisms for both active and passive transport systems 2.4 Understand that all of the body’s processes occur at the cellular level 2.5 Understand that maintaining a cell’s boundaries is vital to life 2.6 Define the 4 major tissue types and their functions 2.7 Describe the specific structure and function of each tissue within the 4 major tissue categories 2.8 Identify the steps to tissue repair 2.9 Define tissue & their relationship to organs 2.10 Apply the structure and function of tissues to the organs we’ll study in detail in future units

Cellular/Plasma Membrane Separates cell contents from the surrounding environment Very dynamic in many cellular activities **Remember: All processes within the body are actually cellular processes!!

Plasma Membrane Structure

Plasma Membrane Structure Phospholipids Proteins in the membrane can be: Receptors for hormones Specialized channels to transport materials Carriers that bind to substances and carry them through the lipid bilayer.

Plasma Membrane Structure Glycoproteins Sugar clusters attached to proteins Determines blood type Receptors for bacteria, viruses and toxins Cholesterol Stabilizes membrane and keeps it fluid

Cell Physiology Cells metabolize: use nutrients to build new materials break down substances make ATP digest foods dispose of waste reproduce grow move and respond to stimuli

Membrane Transport Intracellular Fluid – a solution within the cells containing small amounts of gases, nutrients & salts (solute) all dissolved in water (solvent). Intercellular/Interstitial Fluid – the solution surrounding the cells, derived from blood, very nutritious (amino acids, fatty acids, vitamins), also contains hormones, salts and waste products and all dissolved in water (solvent). Exchanges with the cell occur here.

Membrane Transport How do substances move into and out of the cell? The cell membrane is Selectively Permeable: it allows some substances into the cell. How do substances move into and out of the cell? Passive Transport 2. Active Transport

Membrane Transport Passive Transport – substances move into or out of the cell down the concentration gradient not requiring energy. Diffusion – movement of gases, & other substances 2. Osmosis - movement of water (hypertonic, hypotonic, isotonic solutions)

Membrane Transport Active Transport – substances move into or out of the cell against the concentration gradient which requires energy. Ion pumps Large molecules Chemical composition

Histology The study of…..? Tissues Definitions: Lacking a blood supply Avascular: Innervated: Tissues Lacking a blood supply Has a nerve supply

4 Major Types of Tissue Names and Functions: Epithelial: protects, secretes, absorbs & forms boundaries Connective: supports & protects Muscular: contracts Nervous: transmits impulses

Epithelial Tissue Special characteristics: Avascular Innervated Cells fit closely, forming continuous sheets Regenerates quickly with sufficient nourishment Examples: Skin, membranes that line organs and cavities & glands (endocrine& exocrine).

Epithelial Classification By Shape By Layers

Epithelial Tissue

Connective Tissue Special Characteristics: Living cells surrounded by a non-living extracellular matrix which varies the rigidity of connective tissue from solid to liquid Some vascularized, others not Most abundant tissue in the body

Connective Tissue Types Bone – solid matrix, well vascularized, heals well. Blood – liquid matrix Cartilage – matrix more rubbery, heals slowly, not well vascularized. Adipose (fat) Tendons and ligaments (heal slowly)

Connective Tissue

Muscle Tissue Special characteristics: Highly cellular, well vascularized Muscle cell = muscle fiber

Muscle Tissue 3 types: Skeletal muscle: voluntary, attached to bones; causes movement & expressions Cardiac: involuntary; contract to propel blood through vessels Smooth: lines walls of hollow organs; propels substances through organs

Muscle Tissue

Nervous Tissue Generates and conducts nervous impulses. Makes up the nervous system: neurons, brain and spinal chord.

Tissue Repair Tissue Repair is dependant on severity of injury and type of tissue damaged Regeneration: replacement of destroyed tissue with the same tissue Fibrosis: replacement of destroyed tissue with fibrous connective tissue (scar tissue)

Specific Tissue Repair Regenerates well Epithelium, fibrous connective tissue and bone Regenerates poorly Skeletal muscle, cardiac tissue, nervous tissue Scar tissue Strong, lacks flexibility, unable to perform normal functions