human anatomy and physiology i chapter 3 - part 1 the cell instructor: mary holman

Human Anatomy and Physiology I

Chapter 3 - Part 1The Cell

Instructor: Mary Holman

Levels of Organization

Subatomic particles

Atom

Molecule

Macromolecule

Organelle

Cell

Tissue

Organ

Organ system

Organism

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig 1.3

Cells

• Basic units of all living things• Differentiate into many different types• All cell types have some basic

characteristics in common

CytologyThe study of cellular structure

Fig. 3.2

(b) Epithelial cells protect underlying cells. (c) Muscle cells contract, pulling structures closer together.

(a) A nerve cell transmits impulses from one body part to another.


Fig. 3.2

Fig. 3.3

Microtubules

Flagellum

Nuclear envelope

Basal body

Chromatin

Ribosomes

Cell membrane

Mitochondrion

Cilia

Microtubules

Microtubule

Golgiapparatus

Secretoryvesicles

Centrioles

Microvilli

Lysosomes

SmoothEndoplasmicreticulum

RoughEndoplasmicreticulum

Nucleolus

Nucleus

Phospholipid bilayer


Pg 86

Fig. 3.3

Cell Membrane also called Plasma Membrane

• Outer surface of the cell

• Composed of phospholipid bi-layer

• Selectively permeable

• Protein molecules embedded in the membrane control entrance and exit of molecules

C

H H

HH

C

H

H

N

O

O

Fatty acid

Fatty acid

O

POCH

O–

Phosphate portion

(the unshaded portion may vary)

H

CH

C

H

H

O


Fig. 2.15bA Phospholipid Molecule

Fig. 2.15c

Schematic representationof a phospholipid molecule

Water-insoluble(hydrophobic) “tail”

Water-soluble(hydrophilic) “head”


Cell membrane

“Heads” ofphospholipid

“Tails” ofphospholipid


Hydrophilic

Middle of membrane

Hydrophobic

Fig. 3.6b

cytoplasm

Fig. 3.7

Doublelayer ofphospholipidmolecules

Fibrous protein

Extracellular sideof membrane

Cytoplasmic sideof membrane

Carbohydrate

Hydrophobicfatty acid“tail”

Hydrophilicphosphate“head”

Cholesterolmolecules

Globularprotein

GlycolipidGlycoprotein


Fig. 3.7

Nucleus

• Surrounded by a nuclear membrane which has pores to the cytoplasm

• Contains a nucleolus consisting primarily of ribonucleic acid (RNA)

• The nucleoplasm contains darkly staining chromatin

Fig. 3.19a

Nuclearpores

Nucleus

Nucleolus

Chromatin

Nuclearenvelope

Fig. 3.19The Cell Nucleus

Fig. 3.19b

Nucleolus

Chromatin

Nuclearenvelope


© Stephen L. Wolfe 7,500x

Fig. 3.19b

Cytoplasm

• Cellular material outside the nucleus but inside the cellular membrane

• Consists of a fluid portion called cytosol, a cytoskeleton, organelles, and inclusions

Microfilaments

• Slender fibers of the protein actin

• Bundles of microfilaments along with microtubules provide the framework of the cytoskeleton

• Connect to cellular components providing a matrix to the cytoplasm and lending strength

Microtubules

• Long slender hollow tubes made up of the protein tubulin

•Two to three times larger in diameter than microfilaments

• Provide the framework for movement of organelles within the cell

• Basic component of centrioles, cilia, and flagella

Fig. 3.18a

MitochondrionNucleus

Roughendoplasmicreticulum

Cell membrane

Microfilaments Ribosome Microtubules

Vesicle


Fig. 3 18a

Microtubules

MicrofilamentsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.© M. Schliwa/Visuals Unlimited

Fig. 3.17

35,000x

Kirschner MW, Suter MM, Weingarten MD, Littman DR: The role of in the assembly of microtubules in vitro. Annals NY Acad Sci, 253:90-106, 1975.

Weingarten MD, Suter MM, Littman DR, Kirschner MW: Properties of the depolymerization products of microtubules from mammalian brain. Biochemistry,

13:5529-5537, 1974.

Organelles

Small structures within cells with specialized functions

The number and type of organelles within a specific cell are related to the specific structure and function of that cell

Ribosomes

• Site of protein synthesis

• Non-membranous

• Scattered throughout the cytoplasm and attached to endoplasmic reticulum (ER)

• Composed of two sub-units

• Subunits are manufactured

separately in the nucleolus

ER membrane

Ribosomes

(a)


© Don W. Fawcett/Photo Researchers, Inc. 28,500x

Fig. 3.9a

Ribosomes on the Endoplasmic Reticulum

Endoplasmic Reticulum (ER)• Most extensive structure within the cytoplasm

• Composed of broad, flattened, interconnected sacs and tubules

• Interior spaces called cisternae

• Provides pathway for intracellular transport of molecules

• Called Rough ER (RER) when covered with ribosomes

ER Membranes

Ribosomes


Endoplasmic ReticulumFig. 3.9

Smooth ER


Fig. 3.9c

Golgi Apparatus• Connected to Rough ER (RER)

• Composed of stacks of flattened

membranous sacs called cisternae

• Modifies, packages, and distributes

proteins and lipids made on rough and

smooth ER

• Receives and transports molecules via

vesicles

Fig. 3.10b

Golgiapparatus

Nucleus

Cytosol

Transportvesicle

Secretion

Cell membrane

Nuclearenvelope



Fig. 3.10b Golgi Apparatus

Nucleus

Fig. 3.10a

Golgiapparatus


Transportvesicle

(a)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

© Gordon Leedale/Biophoto Associates

48,500x

Golgi ApparatusFig.3.10a

Vesicles

• Small membranous sacs that vary in size and contents

• Form by pinching off of small pieces of membrane that surround a tiny amount of liquid or solid

• Method of distributing molecules within a cell and/or into and out of cell

Fig. 3.11

Carbohydrates

Cell membrane

Mitochondrion

Lysosome Nuclear poreNuclear envelope

mRNAMilkprotein

Lipids areSynthesizedin the smoothEndoplasmicreticulum (ER).

Most proteins are synthesizedOn ribosomes associated withMembranes of the rough ER,Using amino acids in the cytosol.

Sugars are synthesized in thesmooth ER and Golgi apparatusand may be attached to proteinsor secreted in vesicles.

Proteins are secreted fromvesicles that bud off of theGolgi apparatus.

Fat droplets pick up a layer oflipid from the cell membraneas they exit the cell.

2

3

4

5

6

7

Milk protein genes aretranscribed into mRNA.

1

mRNA exits throughNuclear pores.

Milk Proteinin Golgivesicle


Fig 3.11 pg 93

Mitochondrion

• Rod-shaped bodies with double- layered walls

• Inner layer has many infoldings called cristae

• Major site of energy (ATP) production

• Have their own DNA and ribosomes which are inherited solely from the mother

Lysosomes

• Membrane-enclosed vesicles of varying shape

• Contain a variety of enzymes

• Clean up the cell by destroying debris, unnecessary molecules, aging organelles and foreign particles

• Can play a role in facilitating cell death

Peroxisomes

• Similar to lysosomes in structure but usually smaller

• Contain enzymes for breaking down various often toxic substances

peroxidases and catalase

•Most abundant in liver and kidney cells which are active in detoxification

Centrosome

• Located near the nucleus

• Consists of 2 non-membranous

cylinders - centrioles, at right angles to each other

• Made up of microtubules

• Distribute chromosomes during cell division by forming spindle fibers

Fig. 3.14b Centriole(cross-section)

Centriole(longitudinal section)


Centrioles

Pg 96

Fig. 3.14a

(a)

Centriole(cross-section)

Centriole(longitudinal section)


a: © Don W. Fawcett/Visuals Unlimited

120,000x

Fig. 3.14a Centrioles

Cilia and Flagella• Hair-like appendages on some cells

• Function in providing movement

• Both originate from centrioles and are made up of microtubules

• Cilia are usually <20 um long

• Flagella can be thousands of um in length

• The only human cell with a flagellum is the sperm cell

Fig. 3.15a

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.© Oliver Meckes/Photo Researchers, Inc.

Epithelial cell lining the Respiratory Tract

Cilia 5,400x

Fig. 3.15a

Fig. 3.3

Microtubules

Flagellum

Nuclear envelope

Basal body

Chromatin

Ribosomes

Cell membrane

Mitochondrion

Cilia

Microtubules

Microtubule

Golgiapparatus

Secretoryvesicles

Centrioles

Microvilli

Lysosomes

SmoothEndoplasmicreticulum


Nucleolus

Nucleus

Phospholipid bilayer


Pg 78


Microvilli

Cell membrane

Mitochondrion

Golgi apparatus

Nucleolus

Nucleus

(a)

Lumen Microvilli

(b)

Roughendoplasmicreticulum

Cytoplasm ofepithelial cell

b: © The McGraw-Hill Companies, Inc./Al Telser, photographer 16,000x

Intestinal Epithelial Cell

Chap 17 pg 678

human anatomy and physiology i chapter 3 - part 1 the cell instructor: mary holman

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