Anatomy and Physiology 1 BMS1005 Lecture PDF

Anatomy and physiology 1 BMS1005 Cells, Tissue and Homeostasis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cell physiology Copyright © 2006 Pearson Education, Inc., publishing as...

Anatomy and physiology 1 BMS1005 Cells, Tissue and Homeostasis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cell physiology Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cell Theory  The cell is the basic structural and functional unit of life  Organismal activity depends on individual and collective activity of cells  Biochemical activities of cells are dictated by subcellular structure  Continuity of life has a cellular basis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Chromatin Nuclear envelope Nucleolus Nucleus Plasma Smooth endoplasmic membrane reticulum Cytosol Lysosome Mitochondrion Centrioles Centrosome Rough matrix endoplasmic reticulum Ribosomes Golgi apparatus Microvilli Secretion being released from cell by exocytosis Microfilament Microtubule Intermediate Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings filaments Peroxisome Figure 3.2  Plasma Membrane  Separates intracellular fluids from extracellular fluids  Plays a dynamic role in cellular activity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Fluid Mosaic Model  Double bilayer of lipids with imbedded, dispersed proteins  Bilayer consists of phospholipids, cholesterol, and glycolipids  Glycolipids are lipids with bound carbohydrate  Phospholipids have hydrophobic and hydrophilic bipoles PLAY Membrane Structure Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Membrane Junctions  Tight junction – impermeable junction that encircles the cell  Desmosome – anchoring junction scattered along the sides of cells  Gap junction – a nexus that allows chemical substances to pass between cells Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cytoplasm  Cytoplasm:– material between plasma membrane and the nucleus  Cytosol:– largely water with dissolved protein, salts, sugars, and other solutes  Cytoplasmic organelles: – metabolic machinery of the cell  Inclusions: – chemical substances such as glycosomes, glycogen granules, and pigment Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cytoplasmic Organelles  Specialized cellular compartments  Membranous  Mitochondria, peroxisomes, lysosomes, endoplasmic reticulum)‫(الشبكات‬, and Golgi apparatus  Non membranous  Cytoskeleton, centrioles, and ribosomes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Mitochondria  Double membrane structure with shelf-like cristae  Provide most of the cell’s ATP via aerobic cellular respiration  Contain their own DNA and RNA Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Ribosomes  Granules containing protein and rRNA  Site of protein synthesis  Free ribosomes synthesize soluble proteins  Membrane-bound ribosomes synthesize proteins to be incorporated into membranes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Endoplasmic Reticulum (ER)  Interconnected tubes and parallel membranes enclosing cisternae  Continuous with the nuclear membrane  Two varieties – rough ER and smooth ER Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Rough (ER)  External surface studded with ribosomes  Manufactures all secreted proteins  Responsible for the synthesis of integral membrane proteins and phospholipids for cell membranes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Smooth ER  Tubules arranged in a looping network  Catalyzes the following reactions in various organs of the body  In the liver – lipid and cholesterol metabolism, breakdown of glycogen and, along with the kidneys, detoxification of drugs  In the testes – synthesis of steroid-based hormones Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Golgi Apparatus  Stacked and flattened membranous sacs  Functions in modification, concentration, and packaging of proteins  Transport vessels from the ER fuse with the cis face of the Golgi apparatus Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Lysosomes  Spherical membranous bags containing digestive enzymes  Digest ingested bacteria, viruses, and toxins  Degrade nonfunctional organelles  Breakdown glycogen and release thyroid hormone  Breakdown non useful tissue  Breakdown bone to release Ca2+  Secretory lysosomes are found in white blood cells, immune cells, and melanocytes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Endomembrane System  System of organelles that function to:  Produce, store, and export biological molecules  Degrade potentially harmful substances  System includes:  Nuclear envelope, smooth and rough ER, lysosomes, vacuoles, transport vesicles, Golgi apparatus, and the plasma membrane PLAY Endomembrane System Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Peroxisomes  Membranous sacs containing oxidases and catalases  Detoxify harmful or toxic substances  Neutralize dangerous free radicals  Free radicals – highly reactive chemicals with unpaired electrons (i.e., O2–) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cytoskeleton  The “skeleton” of the cell  Dynamic, elaborate series of rods running through the cytosol  Consists of microtubules ‫انيببات‬, microfilaments, and intermediate filaments Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Microtubules  Dynamic, hollow tubes made of the spherical protein tubulin  Determine the overall shape of the cell and distribution of organelles Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Microfilaments  Dynamic strands of the protein actin  Attached to the cytoplasmic side of the plasma membrane  Braces and strengthens the cell surface  Attach to CAMs and function in endocytosis and exocytosis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Intermediate Filaments  Tough, insoluble protein fibers with high tensile strength  Resist pulling forces on the cell and help form desmosomes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Centrioles  Small barrel-shaped organelles located in the centrosome near the nucleus  Pinwheel array of nine triplets of microtubules  Organize mitotic spindle during mitosis  Form the bases of cilia and flagella Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Cilia  Whip-like, motile cellular extensions on exposed surfaces of certain cells  Move substances in one direction across cell surfaces PLAY Cilia and Flagella Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Nucleus  Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets  Gene-containing control center of the cell  Contains the genetic library with blueprints for nearly all cellular proteins  Dictates the kinds and amounts of proteins to be synthesized Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Nucleus Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.28a  Nuclear Envelope  Outer membrane is continuous with the rough ER and is studded with ribosomes  Inner membrane is lined with the nuclear lamina, which maintains the shape of the nucleus  Pore complex regulates transport of large molecules into and out of the nucleus Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Nucleoli  Dark-staining spherical bodies within the nucleus  Site of ribosome production Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Chromatin  Threadlike strands of DNA and histones  Arranged in fundamental units called nucleosomes  Form condensed, barlike bodies of chromosomes when the nucleus starts to divide Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.29  Tissues Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Tissues  Groups of cells similar in structure and function  The four types of tissues  Epithelial  Connective  Muscle  Nerve Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Epithelial Tissue  Cellularity:– composed almost entirely of cells  Special contacts:– form continuous sheets held together by tight junctions and desmosomes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Epithelial Tissue  Supported by connective tissue  Avascular but innervated: – contains no blood vessels but supplied by nerve fibers  Regenerative:– rapidly replaces lost cells by cell division Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Classification of Epithelia  Simple or stratified Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.1a  Classification of Epithelia  Squamous, cuboidal, or columnar Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.1b  Epithelia: Simple Squamous Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.2a  Epithelia: Simple Cuboidal Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.2b  Epithelia: Simple Columnar Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.2c  Epithelia: Stratified Squamous Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.2e  Connective Tissue  Found throughout the body; most abundant and widely distributed in primary tissues  Connective tissue proper  Cartilage  Bone  Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Functions of Connective Tissue  Binding and support  Protection  Insulation  Transportation Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Structural Elements of Connective Tissue  Ground substance:– unstructured material that fills the space between cells  Fibers:– collagen, elastic, or reticular  Cells:– fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Areolar Connective Tissue: Model Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.8  Connective Tissue Proper: Loose Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9a  Connective Tissue Proper: Loose Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9b  Connective Tissue Proper: Loose Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9c  Connective Tissue Proper: Dense Regular Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9d  Connective Tissue Proper: Dense Irregular Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9e  Connective Tissue: Hyaline Cartilage Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9f  Connective Tissue: Elastic Cartilage Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9g  Connective Tissue: Fibrocartilage Cartilage Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9h  Connective Tissue: Bone (Osseous Tissue) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9i  Connective Tissue: Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.9j  Nervous Tissue Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.10  Muscle Tissue: Skeletal Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.11a  Muscle Tissue: Cardiac Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.11b  Muscle Tissue: Smooth Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 4.11c  Homeostasis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Homeostasis  Homeostasis:– ability to maintain a relatively stable internal environment in an ever-changing outside world  The internal environment of the body is in a dynamic state of equilibrium  Chemical, thermal, and neural factors interact to maintain homeostasis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Homeostatic Control Mechanisms  Variables produce a change in the body  The three interdependent components of control mechanisms:  Receptor – monitors the environments and responds to changes (stimuli)  Control center – determines the set point at which the variable is maintained  Effector – provides the means to respond to stimuli Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Homeostatic Control Mechanisms 3 Input: Control Information center 4 Output: sent along Information sent afferent along efferent pathway to pathway to Receptor (sensor) Effector 2 Change detected by receptor 5 Response of effector feeds 1 Stimulus: back to Produces change influence in variable magnitude of stimulus and Variable (in homeostasis) returns variable to homeostasis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4  Negative Feedback  In negative feedback systems, the output shuts off the original stimulus Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Positive Feedback  In positive feedback systems, the output enhances or exaggerates the original stimulus  Example: Regulation of blood clotting Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.6  Homeostatic Imbalance  Disturbance of homeostasis or the body’s normal equilibrium  Overwhelming the usual negative feedback mechanisms allows destructive positive feedback mechanisms to take over Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings