Chapter 2_Cells and Tissues PDF

Chapter 3 Cells and Tissues By: PM TS. DR. CHE WAN SHARIFAH ROBIAH MOHAMAD Part 1: Cells as Structural Units of Life Cells are the basic building blocks of all living organisms. The human body is composed of trillions of cells, each with a specific structure and function. These...

Chapter 3 Cells and Tissues By: PM TS. DR. CHE WAN SHARIFAH ROBIAH MOHAMAD Part 1: Cells as Structural Units of Life Cells are the basic building blocks of all living organisms. The human body is composed of trillions of cells, each with a specific structure and function. These microscopic units carry out all the essential processes that keep us alive, from metabolism and digestion to reproduction and growth. 1 Structural Units 2 Trillions of Cells Cells are the fundamental units of structure and The human body contains an estimated 50 to 100 function in all living organisms. trillion cells. The Cell Theory The Cell Theory is a cornerstone of biology, providing a framework for understanding the organization and function of living things. It states that all living organisms are composed of cells, that the cell is the basic unit of life, and that all cells arise from pre-existing cells. 1 Basic Unit of Life A cell is the fundamental structural and functional unit of living organisms. 2 Collective Activities The activity of an organism depends on the collective activities of its cells. 3 Structure and Function The biochemical activities of cells are dictated by their structure (anatomy), which determines their function (physiology). 4 Cellular Basis of Life Continuity of life has a cellular basis. Cellular Composition Cells are primarily composed of four key elements: carbon, hydrogen, oxygen, and nitrogen. These elements combine to form the essential molecules of life, including proteins, carbohydrates, lipids, and nucleic acids. Water, which makes up about 60% of a cell's volume, provides a vital medium for cellular processes. Carbon A fundamental element in organic molecules. Hydrogen A key component of water and many organic molecules. Oxygen Essential for cellular respiration and energy production. Nitrogen A key component of proteins and nucleic acids. Anatomy of a Generalized Cell A typical cell can be divided into three main regions: the nucleus, the cytoplasm, and the plasma membrane. Each region plays a crucial role in maintaining the cell's structure and function. Nucleus Cytoplasm Plasma Membrane The control center of the cell, The cellular material outside the The outer boundary of the cell, containing DNA. nucleus and inside the plasma regulating the passage of substances membrane, containing organelles in and out. and cytosol. Anatomy of Nucleus 1 Nuclear Envelope A double membrane that bounds the nucleus, containing pores for exchange of materials. 2 Nucleolus The site of ribosome assembly, which migrate to the cytoplasm for protein synthesis. 3 Chromatin Composed of DNA wound around histones, scattered throughout the nucleus and condensing into chromosomes during cell division. The Nucleus: Control Center of the Cell The nucleus is the cell's control center, housing the genetic material known as DNA. DNA contains the instructions for building proteins, which are essential for all cellular functions. The nucleus also plays a vital role in cell reproduction. Control Center Genetic Material Cell Reproduction The nucleus directs cellular activities. Contains DNA, the blueprint for protein Plays a crucial role in cell division. synthesis. The Plasma Membrane: The Cell's Boundary The plasma membrane is a selectively permeable barrier that encloses the cell's contents and separates them from the surrounding environment. It regulates the passage of substances in and out of the cell, ensuring the proper balance of nutrients, waste products, and other essential molecules. Phospholipid Bilayer Two layers of phospholipids arranged "tail to tail." Cholesterol and Proteins Cholesterol and proteins are scattered among the phospholipids. Sugar Groups Sugar groups may be attached to the phospholipids, forming glycolipids. The Cytoplasm The cytoplasm is the cellular material outside the nucleus and inside the plasma membrane. It's the site of most cellular activities and includes cytosol, inclusions, and organelles. Many organelles are membrane-bound, allowing for compartmentalization of their functions. The Cytoplasm: The Cell's Internal Environment The cytoplasm is the cellular material outside the nucleus and inside the plasma membrane. It's a dynamic environment where most cellular activities take place. The cytoplasm contains organelles, which are specialized structures that perform specific functions, and cytosol, a fluid that suspends the organelles and provides a medium for chemical reactions. Organelle Function Mitochondria Energy production (ATP) Ribosomes Protein synthesis Endoplasmic Reticulum Synthesis and transport of molecules Golgi Apparatus Packaging and modification of molecules Lysosomes Digestion of cellular waste Peroxisomes Detoxification and breakdown of free radicals Cytoskeleton Structural support and intracellular transport Protein Synthesis: Building the Molecules of Life Protein synthesis is the process by which cells build proteins, the essential molecules that carry out a wide range of functions, from structural support to enzymatic activity. This process involves two main phases: transcription, in which the genetic information in DNA is copied into mRNA, and translation, in which the mRNA code is translated into a sequence of amino acids, the building blocks of proteins. DNA as a Blueprint Ribosomes: Protein Factories DNA serves as the blueprint for protein synthesis. Ribosomes are the sites of protein synthesis. Cell Division The cell life cycle consists of two major periods: interphase, where the cell grows and carries out metabolic processes, and cell division, where the cell reproduces itself. Cell division involves mitosis, the division of the nucleus, and cytokinesis, the division of the cytoplasm. Cell Division: The Process of Reproduction Cell division is the process by which cells reproduce themselves. It's a fundamental process that allows for growth, repair, and development. The cell cycle consists of two main phases: interphase, during which the cell grows and carries out its metabolic activities, and cell division, during which the cell replicates its genetic material and divides into two daughter cells. 1 Interphase Cell growth and metabolic activities. 2 Mitosis Division of the nucleus. 3 Cytokinesis Division of the cytoplasm. Cell Extensions Cilia Hair-like projections that move materials across the cell surface, such as mucus in the respiratory system. Flagella Whip-like structures that propel the cell, like the sperm cell. Microvilli Tiny, finger-like extensions of the plasma membrane that increase surface area for absorption. Cell Diversity The human body houses over 200 different cell types, each with its unique size, shape, and function. These variations reflect their specialized roles in the body. No Function Example 1 Connect body parts 1. Fibroblast/fibrocyte 1. Secretes fiber-like material 2. RBC 2. Carrier for nutrient, gases and waste 2 Cover and line body 1. Epithelial cell 1. In sheets condition (serosa epithelia), resist tearing organ during movement (heartbeat, breathing process) 3. Move organ and body 1. Skeletal muscle 1. Contractile filament allow cells to shorten parts 2. Smooth muscle 4. Stored nutrient 1. Adipose cells 1. Storage lipid/TGA in cytoplasm 5. Fight disease 1. WBC 1. Digest pathogen 2. Macrophage 6. Gathers information 1. Nerves cell (neuron) 1. receives/transmits message/electrical stimulus and control body function 7 Reproduction 1. Oocytes 1. offspring/new generations 2. Sperms Cell Diversity Cell Physiology oMetabolize oDigest food oDispose of wastes oReproduce oGrow oMove oRespond to a stimulus Membrane Transport The plasma membrane is selectively permeable, allowing some substances to pass through while excluding others. Membrane transport can be passive, where substances move across the membrane without cellular energy input, or active, where the cell provides energy to drive the transport process. Membrane Transport Intracellular fluid Nucleoplasm and cytosol Solution containing gases, nutrients, and salts dissolved in water Extracellular fluid Fluid on the exterior of the cell (interstitial fluid) Contains thousands of ingredients, such as nutrients, hormones, neurotransmitters, salts, waste products  Membrane Transport Passive processes Active processes substances are transported across the the cell provides the metabolic energy (ATP) to membrane without any input from the cell drive the transport process Types: Type: Diffusion Active transport Simple diffusion (soluble lipid/small mole) Amino acids, sugar, ion Osmosis (highly polar water mole) Sodium-potassium pump Isotonic Example: nerve impulses Hypertonic hypotonic Vesicular transport Facilitated (lipid-insoluble/large mole) Bulk movement Filtration Types: Water and solutes are forced through a membrane by fluid, or Exocytosis hydrostatic, pressure endocytosis Example: kidney Phagocytosis (cell eating) Pinocytosis cell drinking) Without utilize ATP Used ATP Too large molecule Movement against concentration gradient Part II: Body Tissues  Basic cell  A tissue is a group of cells ◦ Common embryonic origin ◦ Function together to carry out specialized activities  Hard (bone), semisolid (fat), or liquid (blood) BODY TISSUE Tissues Groups of cells with similar structure and function Four primary types: 1. Epithelial tissue (epithelium) 2. Connective tissue 3. Muscle tissue 4. Nervous tissue Types of tissues Types Location functions Epithelial Body covering (skin) Covers body surfaces Body lining (serosa) Lines hollow organs, body cavities, duct Glandular tissue (endocrine) Forms glands Connective Connected body part (blood, Protects, supports, and binds organs. fibrocytes) Stores energy as fat Abundance in body provides immunity Muscular Skeletal (muscle) Generates the physical force needed to make Cardiac (heart) body Smooth (GI system) Skeletal muscle, heart muscle, and walls of hollow organs Structures move and generate body heat Nervous Neuron and supported cell Detect changes in body and responds by generating nerve impulses Epithelial Tissue Locations: Body coverings  Functions: Body linings  Protection Glandular tissue  Absorption  Filtration  Secretion Epithelial Tissue Hallmarks of epithelial tissues: Cover and line body surfaces Often form sheets with one free surface, the apical surface, and an anchored surface, the basement membrane Avascular (no blood supply) Regenerate easily if well nourished  Epithelial Tissue Classification of epithelia Number of cell layers Simple—one layer Stratified—more than one layer Shape of cells Squamous—flattened, like fish scales Cuboidal—cube-shaped, like dice Columnar—shaped like columns TABLE 3.17c Classification and functions of epithelia. Number of layers One layer: simple epithelial More than one layer: stratified tissues epithelial tissues Squamous Diffusion and filtration Secretion in Protection serous membranes Example: Skin Example: Lung Cuboidal Secretion and absorption; ciliated Protection; these tissue types are rare types in humans propel mucus or reproductive cells Example: Columnar Secretion and absorption; ciliated Protection; these tissue types are rare types in humans propel mucus or reproductive cells Transitional No simple transitional epithelium exists Protection; stretching to accommodate distension of urinary structures Epithelial Tissue Simple epithelia Functions in absorption, secretion, and filtration Very thin (so not suited for protection)  Epithelial Tissue Simple squamous epithelium Single layer of flat cells Locations—usually forms membranes Lines air sacs of the lungs Forms walls of capillaries Forms serous membranes (serosae) that line and cover organs in ventral cavity Functions in diffusion, filtration, or secretion in membranes Figure 3.18a Types of epithelia and examples of common locations in the body. Air sacs of lungs Nucleus of Nuclei of squamous squamous epithelial cell epithelial cells Basement membrane Photomicrograph: Simple squamous epithelium forming part of the alveolar (a) Diagram: Simple squamous (air sac) walls (275×). Epithelial Tissue Simple cuboidal epithelium Single layer of cube like cells Locations Common in glands and their ducts Forms walls of kidney tubules Covers the surface of ovaries Functions in secretion and absorption; ciliated types propel mucus or reproductive cells Figure 3.18b Types of epithelia and examples of common locations in the body. Nucleus of Simple simple cuboidal cuboidal epithelial epithelial cells cell Basement Basement membrane membrane Connective tissue Photomicrograph: Simple cuboidal (b) Diagram: Simple cuboidal epithelium in kidney tubules (250×). Epithelial Tissue Simple columnar epithelium Single layer of tall cells Goblet cells secrete mucus Locations Lining of the digestive tract from stomach to anus Mucous membranes (mucosae) line body cavities opening to the exterior Functions in secretion and absorption; ciliated types propel mucus or reproductive cells Figure 3.18c Types of epithelia and examples of common locations in the body. Nuclei of simple Mucus of a columnar epithelial cells goblet cell tend to line up Simple columnar epithelial cell Basement Basement membrane membrane Photomicrograph: Simple columnar (c) Diagram: Simple columnar epithelium of the small intestine (575×). Epithelial Tissue Pseudostratified columnar epithelium All cells rest on a basement membrane Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification Location: respiratory tract, where it is ciliated and known as pseudostratified ciliated columnar epithelium Functions in absorption or secretion Figure 3.18d Types of epithelia and examples of common locations in the body. Pseudo- stratified Cilia epithelial layer Pseudostratified Basement epithelial layer membrane Basement Nuclei of membrane pseudostratified cells do not line up Connective tissue Photomicrograph: Pseudostratified (d) Diagram: Pseudostratified (ciliated) ciliated columnar epithelium lining columnar the human trachea (560×). Epithelial Tissue Stratified epithelia Consist of two or more cell layers Function primarily in protection  Epithelial Tissue Stratified squamous epithelium Most common stratified epithelium Named for cells present at the free (apical) surface, which are squamous Functions as a protective covering where friction is common Locations—lining of the: Skin (outer portion) Mouth Esophagus Figure 3.18e Types of epithelia and examples of common locations in the body. Nuclei Stratified squamous epithelium Stratified squamous epithelium Basement Basement membrane membrane Connective Photomicrograph: Stratified tissue squamous epithelium lining of (e) Diagram: Stratified squamous the esophagus (140×). Epithelial Tissue Stratified cuboidal epithelium—two layers of cuboidal cells; functions in protection Stratified columnar epithelium—surface cells are columnar, and cells underneath vary in size and shape; functions in protection Stratified cuboidal and columnar Rare in human body Found mainly in ducts of large glands Epithelial Tissue Transitional epithelium Composed of modified stratified squamous epithelium Shape of cells depends upon the amount of stretching Functions in stretching and the ability to return to normal shape Location: lining of urinary system organs Figure 3.18f Types of epithelia and examples of common locations in the body. Basement membrane Transi- tional epithelium Transitional Basement epithelium membrane Connective tissue Photomicrograph: Transitional epithelium lining of the bladder, relaxed state (270×); surface rounded cells (f) Diagram: Transitional flatten and elongate when the bladder fills with urine.  Epithelial Tissue Glandular epithelia One or more cells responsible for secreting a particular product Secretions contain protein molecules in an aqueous (water-based) fluid Secretion is an active process  Epithelial Tissue Two major gland types develop from epithelial sheets Endocrine glands Ductless; secretions (hormones) diffuse into blood vessels Examples include thyroid, adrenals, and pituitary Exocrine glands Secretions empty through ducts to the epithelial surface Include sweat and oil glands, liver, and pancreas (both internal and external)  Connective Tissue Found everywhere in the body to connect body parts Includes the most abundant and widely distributed tissues Functions Protection Support Binding Connective Tissue Characteristics of connective tissue Variations in blood supply Some tissue types are well vascularized Some have a poor blood supply or are avascular Extracellular matrix Nonliving material that surrounds living cells Connective Tissue Two main elements of the extracellular matrix 1. Ground substance—mostly water, along with adhesion proteins and polysaccharide molecules 2. Fibers Collagen (white) fibers Elastic (yellow) fibers Reticular fibers (a type of collagen) Connective Tissue Types of connective tissue from most rigid to softest, or most fluid: Bone Cartilage Dense connective tissue Loose connective tissue Blood Connective Tissue Bone (osseous tissue) Composed of: Osteocytes (bone cells) sitting in lacunae (cavities) Hard matrix of calcium salts Large numbers of collagen fibers Functions to protect and support the body Figure 3.19a Connective tissues and their common body locations. Osteocytes (bone cells) in lacunae Central canal Lacunae (a) Diagram: Bone Photomicrograph: Cross-sectional view of bone (165×).  Connective Tissue Cartilage Less hard and more flexible than bone Found in only a few places in the body Chondrocyte (cartilage cell) is the major cell type Types Hyaline cartilage Fibrocartilage Elastic cartilage  Connective Tissue Hyaline cartilage Most widespread type of cartilage Abundant collagen fibers hidden by a glassy, rubbery matrix Locations Trachea Attaches ribs to the breastbone Covers ends of long bones Entire fetal skeleton prior to birth Epiphyseal (growth) plates in long bones Figure 3.19b Connective tissues and their common body locations. Chondrocyte (cartilage cell) Chondrocyte in lacuna Lacunae Matrix (b) Diagram: Hyaline cartilage Photomicrograph: Hyaline cartilage from the trachea (400×). Connective Tissue Elastic cartilage (not pictured) Provides elasticity Location: supports the external ear Fibrocartilage Highly compressible Location: forms cushionlike discs between vertebrae of the spinal column Figure 3.19c Connective tissues and their common body locations. Chondrocytes in lacunae Chondro- cytes in lacunae Collagen fiber Collagen fibers (c) Diagram: Fibrocartilage Photomicrograph: Fibrocartilage of an intervertebral disc (150×).  Connective Tissue Dense connective tissue (dense fibrous tissue) Main matrix element is collagen fiber Fibroblasts are cells that make fibers Locations Tendons—attach skeletal muscle to bone Ligaments—attach bone to bone at joints and are more elastic than tendons Dermis—lower layers of the skin Figure 3.19d Connective tissues and their common body locations. Ligament Tendon Collagen fibers Collagen fibers Nuclei of Nuclei of fibroblasts fibroblasts (d) Diagram: Dense fibrous Photomicrograph: Dense fibrous connective tissue from a tendon (475×). Connective Tissue Loose connective tissue Softer, have more cells and fewer fibers than other connective tissues (except blood) Types Areolar Adipose Reticular Connective Tissue Areolar connective tissue Most widely distributed connective tissue Soft, pliable tissue like “cobwebs” Functions as a universal packing tissue and “glue” to hold organs in place Layer of areolar tissue called lamina propria underlies all membranes All fiber types form a loose network Can soak up excess fluid (causes edema) Figure 3.19e Connective tissues and their common body locations. Mucosal epithelium Lamina Elastic propria fibers Collagen fibers Elastic Fibroblast fibers of nuclei matrix Nuclei of fibroblasts Collagen fibers (e) Diagram: Areolar Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (270×).  Connective Tissue Adipose connective tissue An areolar tissue in which adipose (fat) cells dominate Functions Insulates the body Protects some organs Serves as a site of fuel storage Locations Subcutaneous tissue beneath the skin Protects organs, such as the kidneys Fat “depots” include hips, breasts, and belly Figure 3.19f Connective tissues and their common body locations. Nuclei of fat cells Vacuole containing fat droplet Nuclei of fat cells Vacuole containing fat droplet (f) Diagram: Adipose Photomicrograph: Adipose tissue from the subcutaneous layer beneath the skin (570×).  Connective Tissue Reticular connective tissue Delicate network of interwoven fibers with reticular cells (like fibroblasts) Forms stroma (internal framework) of organs Locations Lymph nodes Spleen Bone marrow Figure 3.19g Connective tissues and their common body locations. Spleen White blood cell (lymphocyte) Reticular cell Reticular fibers Blood cell Reticular fibers (g) Diagram: Reticular Photomicrograph: Dark-staining network of reticular connective tissue (400×).  Connective Tissue Blood (vascular tissue) Blood cells surrounded by fluid matrix known as blood plasma Soluble fibers are visible only during clotting Functions as the transport vehicle for the cardiovascular system, carrying: Nutrients Wastes Respiratory gases Figure 3.19h Connective tissues and their common body locations. Blood cells in capillary Plasma (fluid matrix) Neutrophil (white blood cell) White Red blood blood cell cells Monocyte Red (white blood blood cells cell) (h) Diagram: Blood Photomicrograph: Smear of human blood (1290×) Muscle Tissue Function is to contract, or shorten, to produce movement Three types of muscle tissue 1. Skeletal 2. Cardiac 3. Smooth  Muscle Tissue Skeletal muscle tissue Packaged by connective tissue sheets into skeletal muscles, which are attached to the skeleton and pull on bones or skin Voluntarily (consciously) controlled Produces gross body movements or facial expressions Characteristics of skeletal muscle cells Striations (stripes) Multinucleate (more than one nucleus) Long, cylindrical shape Figure 3.20a Types of muscle tissue and their common locations in the body. Striations Multiple nuclei per fiber Part of muscle fiber (a) Diagram: Skeletal muscle Photomicrograph: Skeletal muscle (195×).  Muscle Tissue Cardiac muscle tissue Involuntarily controlled Found only in the heart Pumps blood through blood vessels Characteristics of cardiac muscle cells Striations One nucleus per cell Short, branching cells Intercalated discs contain gap junctions to connect cells together © 2018 Pearson Education, Inc. Figure 3.20b Types of muscle tissue and their common locations in the body. Intercalated discs Nucleus (b) Diagram: Cardiac muscle Photomicrograph: Cardiac muscle (475×).  Muscle Tissue Smooth (visceral) muscle tissue Involuntarily controlled Found in walls of hollow organs such as stomach, uterus, and blood vessels Peristalsis, a wavelike activity, is a typical activity Characteristics of smooth muscle cells No visible striations One nucleus per cell Spindle-shaped cells Figure 3.20c Types of muscle tissue and their common locations in the body. Nuclei Smooth muscle cell (c) Diagram: Smooth muscle Photomicrograph: Sheet of smooth muscle (360×). Nervous Tissue Function is to receive and conduct electrochemical impulses to and from body parts Irritability Conductivity Composed of neurons and nerve support cells Support cells called neuroglia insulate, protect, and support neurons Figure 3.21 Nervous tissue. Brain Nuclei of Spinal neuroglia cord (supporting cells) Nuclei of Cell body neuroglia of neuron (supporting cells) Cell body Neuron of neuron processes Neuron processes Diagram: Nervous tissue Photomicrograph: Neurons (320×) Summary of Tissues © 2018 Pearson Education, Inc. Tissue Repair (Wound Healing) Tissue repair (wound healing) occurs in two ways: 1. Regeneration Replacement of destroyed tissue by the same kind of cells 2. Fibrosis Repair by dense (fibrous) connective tissue (scar tissue) Tissue Repair (Wound Healing) Whether regeneration or fibrosis occurs depends on: 1. Type of tissue damaged 2. Severity of the injury Clean cuts (incisions) heal more successfully than ragged tears of the tissue  Tissue Repair (Wound Healing) Events of tissue repair Inflammation sets the stage Capillaries become very permeable Clotting proteins migrate into the area from the bloodstream A clot walls off the injured area Granulation tissue forms Growth of new capillaries Phagocytes dispose of blood clot and fibroblasts Rebuild collagen fibers Tissue Repair (Wound Healing) Events of tissue repair (continued) Regeneration and fibrosis effect permanent repair Scab detaches Whether scar is visible or invisible depends on severity of wound  Tissue Repair (Wound Healing) Tissues that regenerate easily Epithelial tissue (skin and mucous membranes) Fibrous connective tissues and bone Tissues that regenerate poorly Skeletal muscle Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord PART III: Developmental Aspects of Cells and Tissues Growth through cell division continues through puberty Cell populations exposed to friction (such as epithelium) replace lost cells throughout life Connective tissue remains mitotic and forms repair (scar) tissue With some exceptions, muscle tissue becomes amitotic by the end of puberty Nervous tissue becomes amitotic shortly after birth Developmental Aspects of Cells and Tissues Injury can severely handicap amitotic tissues The cause of aging is unknown, but chemical and physical insults, as well as genetic programming, have been proposed as possible causes Developmental Aspects of Cells and Tissues Neoplasms, both benign and cancerous, represent abnormal cell masses in which normal controls on cell division are not working Hyperplasia (increase in size) of a tissue or organ may occur when tissue is strongly stimulated or irritated Atrophy (decrease in size) of a tissue or organ occurs when the organ is no longer stimulated normally SUMMARY Cell as a basic structure Organelle in animal cell. Modification of cell type Types of human tissue Tissue repair events Nucleus Nucleus Squamous Epithelial Inflammation Cytoplasm Mitochondria Cuboidal Muscular Granulation Membrane cell. Lysosome Columnar Connective regeneration RE Transition. Nerves Golgi apparatus Etc 1 2 3 4 5