Essentials of Human Anatomy & Physiology PDF

Essentials of Human Anatomy & Physiology Thirteenth Edition Global Edition Chapter 3 Cells and Tissues Lecture Presentation by...

Essentials of Human Anatomy & Physiology Thirteenth Edition Global Edition Chapter 3 Cells and Tissues Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Part : CellsI One Cells are the structural units of all living things The human body has 50 to 100 trillion cells Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Overview of the Cellular Basis of Life (2 of 2) Most cells are composed of four elements: 1. Carbon 2. Hydrogen 3. Oxygen 4. Nitrogen Cells are about 60% water Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Anatomy of a Generalized Cell In general, a cell has three main regions or parts: 1. Plasma membrane 2. Nucleus 3. Cytoplasm Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (1 of 9) Transparent barrier for cell contents Contains cell contents Separates cell contents from surrounding environment Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (2 of 9) Fluid mosaic model is constructed of: – Two layers of phospholipids arranged “tail to tail” – Cholesterol and proteins scattered among the phospholipids – Sugar groups may be attached to the phospholipids, forming glycolipids Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.1 Structure of the Plasma Membrane Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (3 of 9) Phospholipid arrangement in the plasma membrane – Hydrophilic (“water loving”) polar “heads” are oriented on the inner and outer surfaces of the membrane – Hydrophobic (“water fearing”) nonpolar “tails” form the center (interior) of the membrane ▪ This interior makes the plasma membrane relatively impermeable to most water-soluble molecules Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (4 of 9) Role of proteins – Responsible for specialized membrane functions: ▪ Enzymes ▪ Receptors for hormones or other chemical messengers ▪ Transport as channels or carriers Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (5 of 9) Role of sugars – Glycoproteins are branched sugars attached to proteins that abut the extracellular space – Glycocalyx is the fuzzy, sticky, sugar-rich area on the cell’s surface Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (6 of 9) Cell membrane junctions – Cells are bound together in three ways: 1. Glycoproteins in the glycocalyx act as an adhesive or cellular glue 2. Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove fashion 3. Special cell membrane junctions are formed, which vary structurally depending on their roles Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (7 of 9) Main types of cell junctions – Tight junctions ▪ Impermeable junctions ▪ Bind cells together into leakproof sheets ▪ Plasma membranes fuse like a zipper to prevent substances from passing through extracellular space between cells Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (8 of 9) Main types of cell junctions – Desmosomes ▪ Anchoring junctions, like rivets, that prevent cells from being pulled apart as a result of mechanical stress ▪ Created by buttonlike thickenings of adjacent plasma membranes Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Plasma Membrane (9 of 9) Main types of cell junctions – Gap junctions (communicating junctions) ▪ Allow communication between cells ▪ Hollow cylinders of proteins (connexons) span the width of the abutting membranes ▪ Molecules can travel directly from one cell to the next through these channels Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.2 Cell Junctions Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Nucleus (1 of 4) Control center of the cell Contains genetic material known as deoxyribonucleic acid, or DNA – DNA is needed for building proteins – DNA is necessary for cell reproduction Three regions: 1. Nuclear envelope (membrane) 2. Nucleolus 3. Chromatin Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.3a Anatomy of the Generalized Animal Cell Nucleus Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.3b Anatomy of the Generalized Animal Cell Nucleus Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Nucleus (2 of 4) Nuclear envelope (membrane) – Consists of a double membrane that bounds the nucleus – Contains nuclear pores that allow for exchange of material with the rest of the cell – Encloses the jellylike fluid called the nucleoplasm Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Nucleus (3 of 4) Nucleolus – Nucleus contains one or more dark-staining nucleoli – Sites of ribosome assembly – Ribosomes migrate into the cytoplasm through nuclear pores to serve as the site of protein synthesis Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Nucleus (4 of 4) Chromatin – Composed of DNA wound around histones (proteins) – Scattered throughout the nucleus and present when the cell is not dividing – Condenses to form dense, rodlike bodies called chromosomes when the cell divides Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (1 of 12) The cellular material outside the nucleus and inside the plasma membrane Site of most cellular activities Includes cytosol, inclusions, and organelles Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (2 of 12) Three major component of the cytoplasm 1. Cytosol: Fluid that suspends other elements and contains nutrients and electrolytes 2. Inclusions: Chemical substances, such as stored nutrients or cell products, that float in the cytosol 3. Organelles: Metabolic machinery of the cell that perform functions for the cell ▪ Many are membrane-bound, allowing for compartmentalization of their functions Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.4 Structure of the Generalized Cell Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (3 of 12) Mitochondria – “Powerhouses” of the cell – Mitochondrial wall consists of a double membrane with cristae on the inner membrane – Carry out reactions in which oxygen is used to break down food into ATP molecules Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (4 of 12) Ribosomes – Made of protein and ribosomal RNA – Sites of protein synthesis in the cell – Found at two locations: ▪ Free in the cytoplasm ▪ Attached to the rough endoplasmic reticulum Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (5 of 12) Endoplasmic reticulum (ER) – Fluid-filled tunnels (or canals) that carry substances within the cell – Continuous with the nuclear membrane – Two types: ▪ Rough ER ▪ Smooth ER Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (6 of 12) Endoplasmic reticulum (ER) – Rough endoplasmic reticulum ▪ Studded with ribosomes ▪ Synthesizes proteins ▪ Transport vesicles move proteins within cell ▪ Abundant in cells that make and export proteins Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.5 Synthesis and Export of a Protein by the Rough ER (1 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.5 Synthesis and Export of a Protein by the Rough ER (2 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.5 Synthesis and Export of a Protein by the Rough ER (3 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.5 Synthesis and Export of a Protein by the Rough ER (4 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.5 Synthesis and Export of a Protein by the Rough ER (5 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (7 of 12) Endoplasmic reticulum (ER) – Smooth endoplasmic reticulum ▪ Lacks ribosomes ▪ Functions in lipid metabolism ▪ Detoxification of drugs and pesticides Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (8 of 12) Golgi apparatus – Appears as a stack of flattened membranes associated with tiny vesicles – Modifies and packages proteins arriving from the rough ER via transport vesicles – Produces different types of packages ▪ Secretory vesicles (pathway 1) ▪ In-house proteins and lipids (pathway 2) ▪ Lysosomes (pathway 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.6 Role of the Golgi Apparatus in Packaging the Products of the Rough ER (1 of 2) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (9 of 12) Lysosomes – Membranous “bags” that contain digestive enzymes – Enzymes can digest worn-out or nonusable cell structures – House phagocytes that dispose of bacteria and cell debris Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (10 of 12) Peroxisomes – Membranous sacs of oxidase enzymes ▪ Detoxify harmful substances such as alcohol and formaldehyde ▪ Break down free radicals (highly reactive chemicals) ▪ Free radicals are converted to hydrogen peroxide and then to water – Replicate by pinching in half or budding from the ER Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (11 of 12) Cytoskeleton – Network of protein structures that extend throughout the cytoplasm – Provides the cell with an internal framework that determines cell shape, supports organelles, and provides the machinery for intracellular transport – Three different types of elements form the cytoskeleton: 1. Microfilaments (largest) 2. Intermediate filaments 3. Microtubules (smallest) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 3.7 Cytoskeletal Elements Support the Cell and Help to Generate Movement Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Cytoplasm (12 of 12) Centrioles – Rod-shaped bodies made of nine triplets of microtubules – Generate microtubules – Direct the formation of mitotic spindle during cell division Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 3.1 Parts of the Cell: Structure and Function (1 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 3.1 Parts of the Cell: Structure and Function (2 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 3.1 Parts of the Cell: Structure and Function (3 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 3.1 Parts of the Cell: Structure and Function (4 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 3.1 Parts of the Cell: Structure and Function (5 of 5) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Cell Extensions Surface extensions found in some cells – Cilia move materials across the cell surface ▪ Located in the respiratory system to move mucus – Flagella propel the cell ▪ The only flagellated cell in the human body is sperm – Microvilli are tiny, fingerlike extensions of the plasma membrane ▪ Increase surface area for absorption Copyright © 2022 Pearson Education, Ltd. All Rights Reserved.