Slide 1 Copyright © 2005. Mosby Inc. All Rights Reserved. Chapter 3 Cells and Tissue

Slide 1Copyright © 2005. Mosby Inc. All Rights Reserved.

Chapter 3Chapter 3

Cells and Tissue


Learning Objectives

Identify and discuss the basic structure and function of the three major components of a cell.

List and briefly discuss the functions of the primary cellular organelles.

Compare the major passive and active transport processes that act to move substances through cell membranes.


Learning Objectives (cont’d.)

Compare and discuss DNA and RNA and their function in protein synthesis.

Discuss the stages of mitosis and explain the importance of cellular reproduction.


Learning Objectives (cont’d.)

• Explain how epithelial tissue is grouped according to shape and arrangement of cells.

• List and briefly discuss the major types of connective and muscle tissue.

• List the three structural components of a neuron.


Chapter 3Lesson 3.1


Size and ShapeSize and Shape Human cells vary considerably in size. All are microscopic. Cells differ notably in shape. Cytoplasm contains specialized organelles

surrounded by a plasma membrane.

Cytoplasm contains specialized organelles. Plasma membrane surrounds each cell. Organization of cytoplasmic substances is

important for life. The small, circular body called the nucleus is

inside the cell.

CompositionComposition


CompositionComposition

GeneralCharacteristicsof the cell


Plasma membrane forms outer boundary of cell only 7 nm (3/10,000,000 of an inch) thick thin two-layered membrane of phospholipids

containing proteins form the framework of the plasma membrane

is selectively permeable

Parts of the CellParts of the Cell

Cytoplasm internal living material of cells organelles—small structures that make up most of the

cytoplasmo Ribosomes: may attach to rough endoplasmic

reticulum (ER) or lie free in cytoplasm.


Parts of the Cell (cont’d.)Parts of the Cell (cont’d.)

Endoplasmic reticulum (ER) network of connecting sacs and canals carries substances through cytoplasm

Golgi apparatus group of flattened sacs stacked on one another near

nucleus Mitochondria

composed of inner and outer membranes each contains one DNA molecule


Parts of the Cell (cont’d.)Parts of the Cell (cont’d.) Lysosomes

membranous-walled organelles contain digestive enzymes

Centrioles paired organelles fine tubules that lie at right angles to each other near

the nucleus

Cilia fine hairlike extensions found on free or exposed

surfaces of some cells Flagellum

single projection extending from cell surfaces much larger than cilia


Parts of the Cell (cont’d.)Parts of the Cell (cont’d.)

Nucleus controls every organelle in the cytoplasm,

along with cell reproduction contains the genetic code component structures include nuclear

envelope, nucleoplasm, and chromatin granules


Relationship of Cell Structure and FunctionRelationship of Cell Structure and Function

Regulation of life processes. Survival of species through reproduction

of the individual. Relationship of structure to function is

apparent in number and type of organelles seen in different cells.


Movement of Substances Through Cell MembranesMovement of Substances Through Cell Membranes

Passive transport processes processes do not require added energy and

result in movement “down a concentration gradient”

types of passive transport include: diffusion

o osmosis o dialysis

filtration


Movement of Substances Through Cell Membranes (cont’d.)Movement of Substances Through Cell Membranes (cont’d.)

Passive Transport Processes



Passive transport processes Diffusion

Substances scatter themselves evenly throughout an available space.

It is unnecessary to add energy to the system. Movement is from high to low concentration. Osmosis and dialysis are specialized examples of

diffusion.



Passive transport processes Filtration

Movement of water and solutes through a membrane because of a greater pushing force on one side of the membrane than on the other.

This force is called hydrostatic pressure. Responsible for urine formation.



Active transport processes occurs only in living cells movement of substances is “ against/up

the concentration gradient” requires energy from adenosine

triphosphate (ATP)



Active Transport Processes



Active transport processes Ion pumps

An ion pump is protein complex in cell membrane called a carrier.

Ion pumps use energy from ATP to move substances across cell membranes against their concentration gradients

Phagocytosis and Pinocytosis Both are active transport mechanisms because they

require cell energy. Phagocytosis is a protective mechanism often used

to destroy bacteria. Pinocytosis is used to incorporate fluids or dissolved

substances into cells.


Chapter 3Lesson 3.2


Cell ReproductionCell Reproduction

Mitosis the process of cell reproduction, one cell

divides to become two cells. tied closely to the production of proteins


Cell Reproduction (cont’d.)Cell Reproduction (cont’d.)DNA Molecule and Genetic Information Chromosomes are composed largely of DNA. DNA shaped like a long, narrow spiral

staircase. Each step in the DNA ladder consists of pair of

bases. Only two combinations of bases will occur A-T or

C-G. Called complementary base pairing.


Genetic CodeGenetic Code

DNA Molecule and Genetic Information Genes dictate formation of enzymes and other

proteins by ribosomes. Although the types of base pairs in all

chromosomes are the same, the sequence varies.

Each gene directs the synthesis of a specific protein.

Genetic code—the storage of information in each gene


Genetic Code (cont’d.)Genetic Code (cont’d.)

RNA Molecules and Protein Synthesis Ribonucleic acid (RNA) transfers genetic

information from the nucleus to the cytoplasm. RNA is made up of:

sugar: ribose phosphate nitrogen bases: cytosine, guanine, adenine,

uracil



RNA Molecules and Protein Synthesis Transcription

Double-stranded DNA separates to form messenger RNA (mRNA).

Each strand of mRNA duplicates a particular gene (base-pair sequence) from a segment of DNA.

mRNA molecules pass from the nucleus to the cytoplasm where they direct protein synthesis in ribosomes and ER.



Translation Involves synthesis of proteins in cytoplasm by

ribosome Requires use of information contained in mRNA

to direct the choice and sequencing of the building blocks called amino acids

As amino acids are assembled into proper sequence, a protein strand forms.



Protein synthesis


Cell DivisionCell Division

Reproduction of cell by division of the nucleus (mitosis) and the cytoplasm

DNA Replication Process by which each half of a DNA

molecule becomes a whole molecule identical to the original DNA molecule

Happens before mitosis


Cell Division (cont’d.)Cell Division (cont’d.)Mitosis Process in cell division in which identical chromosomes

(DNA molecules) to each new cell are formed when the original cell divides

Enables cells to reproduce their own kind


Stages of MitosisStages of Mitosis

Prophase—first stage Chromatin granules become organized. Chromosomes (pairs of linked chromatids)

appear. Chromatids are held together by beadlike

structure called centromere. Centrioles move away from each other. Spindle fibers form between centrioles. Nuclear envelope disappears, freeing genetic

material.


Stages of Mitosis (cont’d.)Stages of Mitosis (cont’d.)

Metaphase—second stage Nuclear envelope and nucleolus have

disappeared. Chromosomes align across center of cell. Spindle fibers attach themselves to each

chromatid.



Anaphase—third phase Centromeres break apart. Separated chromatids are now called

chromosomes once again. Chromosomes are pulled to opposite ends of

cell. Cleavage furrow develops at end of anaphase.

Beginning to divide cell into two daughter cells



Telophase—fourth stage Cell division is completed. Nuclei appear in daughter cells. Nuclear envelope and nucleoli appear. Cytoplasm and organelles divide equally. Daughter cells become fully functional.


Chapter 3Lesson 3.3

Epithelial Tissue types


TissuesTissuesEpithelial tissue

Covers body and lines body cavities Cells packed closely together with little matrix Classified by shape and arrangement of cells

Epithelial tissue types simple squamous epithelium

single layer of very thin, irregularly shaped cells transport is function (such as absorption of oxygen

into blood) located in alveoli of lungs, lining of blood, and

lymphatic vessels stratified squamous epithelium

several layers of closely packed cells protection is primary function


Tissues (cont’d.)Tissues (cont’d.)Epithelial tissue types

Simple columnar epithelium Single layer of tall, narrow cells Contain mucus-producing goblet cells

Stratified transitional epithelium Up to 10 layers of roughly cuboidal-shaped cells that

distort to squamous shape when stretched Functions as protection Found in body areas subject to stress and that

stretch, such as urinary bladder Pseudostratified epithelium

Single layer of tall cells that wedge together to appear as if there are two or more layers

Simple cuboidal epithelium Form tubules specialized for secretory activity Usually form clusters called glands


Tissues (cont’d.)Tissues (cont’d.)

Classificationof epithelialtissues



Connective tissue Most abundant tissue in body Most widely distributed tissue in body Multiple types, appearances, and functions Relatively few cells in intercellular matrix Types

Areolar—glue that holds organs together Adipose (fat)—lipid storage is primary function Fibrous—consists of strong, white collagen fibers


Tissues (cont’d.)Tissues (cont’d.)Connective tissue types

Bone—matrix is hard and calcifiedo Forms structural building blocks called osteons o Function in support and protection, stores calcium

Cartilage—chondrocyte is cell typeo Differs from bone because its matrix has the consistency of a firm plastic or gristle-like gel

Blood and Hemopoietic o Blood—matrix is fluido Hemopoietic—bloodlike connective tissue found in marrow cavities



Muscle tissue Types

Skeletal—also called striated or voluntaryo attaches to boneso control is voluntaryo striations apparent when viewed under a microscope



Muscle tissue types Cardiac—also called striated involuntary

o produces regular, involuntary contractions of cardiac muscle to produce heartbeato has faint cross striations and thicker dark bands called intercalated disks

Smooth—also called visceralo involuntary controlo appears smooth; without cross striationso has only one nucleus per fibero forms walls of blood vessels, hollow organs such as intestines and other tube-shaped structures



Nervous tissue Provides rapid communication between body

structures and control of body functions Example is spinal cord tissue Consists of two cell types: neuron and glia

Glia (neuroglia)—supportive and connecting cells

Neurons—conducting cell

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Slide 1 Copyright © 2005. Mosby Inc. All Rights Reserved. Chapter 3 Cells and Tissue