chapter 2

HUMAN ANATOMYFifth Edition

Chapter 1 Lecture

Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings

Chapter 2 Lecture

Chapter 2The Cell

Frederic MartiniMichael TimmonsRobert Tallitsch

Introduction

• Cell theory: – Cells are the smallest structural units that

perform all vital functions.

Figure 2.1a,b,c Different Technique, Different Perspective

The Study of Cells

• The study of cells is cytology:– Light microscopy – Transmission electron microscopy  – Scanning electron microscopy

Figure 2.3 Anatomy of a Typical Cell

Cellular Anatomy

Cells have four types of component:

1) Membranes2) Organelles3) Cytoplasm4) inclusions

Figure 2.4 A Flow Chart for the Study of Cell Structure

Cellular Anatomy

Cell Structure

PLAY Cell Structure

This movie reviews cell structure.

Figure 2.5 The Cell Membrane

The Cell Membrane

The Cell Membrane

• Major functions of the cell membrane can be described:– Regulation of exchange with the

environment– Receptors and ID

Figure 2.6 Diffusion across the Cell Membrane

Membrane Permeability: Passive Processes

• Diffusion

• Osmosis

• Facilitated Diffusion

Membrane Permeability: Active Processes

• Active transport uses enzymes and carrier proteins:– Ions pumps are carrier proteins for charged

particles.– Ions moved regularly by active transport

include Na+, Ca2+, Mg2+, K+

– Ion pumps are specific. – An ion pump that moves two ions

simultaneously in opposite directions is called an exchange pump.

Figure 2.7a Pinocytosis

Membrane Permeability: Active Processes

Figure 2.7b Phagocytosis

Membrane Permeability: Active Processes

Figure 2.8 Receptor-Mediated Endocytosis

Membrane Permeability: Active Processes

Cytoplasm

• The cytoplasm is the general term for the material inside the cell.– It is a fluid very high in protein. – The cytosol is the intracellular fluid:

• It is high in potassium ions.• It contains an overall negative charge.

– Transmembrane potential

• It contains high concentrations of proteins.

– Organelles are structures within the cyto-plasm that have a particular function and very distinct structure.

Nonmembranous Organelles

• The cytoskeleton:– Microfilaments– Microtubules 

• Microvilli

QuickTime™ and a decompressor

are needed to see this picture.

Figure 2.9 The Cytoskeleton

Nonmembranous Organelles

Figure 2.10 Centrioles and Cilia

Nonmembranous Organelles

• Centrioles

• Cilia

• Flagella

Figure 2.11 Ribosomes

Nonmembranous Organelles

• Ribosomes:– 60% RNA and 40% protein– Free ribosomes:

• Float in the cytoplasm

– Fixed ribosomes:• Are attached to the endoplasmic reticulum

Figure 2.12 Mitochondria

Membranous Organelles

• Mitochondria are double membraned organelles. – Cristae are the folds of the inner membrane – Inner fluid is the matrix.

Membranous Organelles

• The nucleus is the control center of the cell.– Nucleoplasm– Nuclear envelope – Perinuclear space– Nuclear pores– Nuclear matrix

Figure 2.13a The Nucleus

Membranous Organelles

Figure 2.14 Chromosome Structure

Membranous Organelles: Nucleus

• Chromosomes: – DNA wrapped

around proteins called histones.

– Nucleosomes– Chromatin

Membranous Organelles

• The ER has four major functions:– Synthesis of all classes of macromolecules– Storage of the manufactured molecules– Transport of substances from on area of the

cell to another– Enzymes in the lumen of the ER provide

detoxification

Figure 2.15 The Endoplasmic Reticulum

Membranous Organelles

Figure 2.16b The Golgi Apparatus

Membranous Organelles

• The three main functions of the Golgi apparatus:– Synthesis and

packaging of secretions.

– Packaging of enzymes for use in the cytosol.

– Renewal and modification of the cell membrane.

Figure 2.18 Lysosomal Functions

Membranous Organelles

• Lysosome function in three manners:

1. Fuse with phagosomes to digest solid materials.

2. Fuse with and recycle damaged organelles.

3. Sometimes rupture a process resulting in autolysis.

Figure 2.19 Cell Attachments

Intercellular Attachment

Figure 2.20 The Cell Life Cycle

The Cell Life Cycle

Figure 2.21 DNA Replication

DNA Replication

Figure 2.22a

Interphase

Figure 2.22b,c

Prophase

Figure 2.22d,e

Metaphase and Anaphase

Figure 2.22f,g

Telophase and Cytokinesis