Essentials of Human Anatomy & Physiology

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Seventh EditionElaine N. Marieb

Chapter 3Cells and Tissues

Journey into the cell….an introduction …..Journey inside the cell (3.5): https://www.youtube.com/watch?v=1fiJupfbSpg

Cells and Tissues

Slide 3.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Both carry out all chemical activities needed to sustain life. ∙Cells are the building blocks of all living things∙Tissues = groups of cells that are similar in structure and functionForm reflects function!

Main Ideas to recall…..

Anatomy of the Cell (in general…)

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∙ All cells share general structures∙ Cells are organized into three main regions

∙Nucleus∙Cytoplasm∙Plasma membrane

Figure 3.1a

The Nucleus

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Control center of the cell

∙ Contains genetic material (DNA)

∙ Largest structure in the cell

Figure 3.1b

I am full of holes!

Plasma Membrane

Slide 3.7bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.2

Plasma Membrane

Lipids: hydrophilic/hydrophobic bilayer that creates the barrier of the cell and environment; used for transport

Proteins: used for transport, cell signaling or communication, anchorage, cellular junctions.

Plasma Membrane

Membrane Proteins: used for transport, cell signaling or communication, anchorage, cellular junctions.

-integral proteins vs peripheral proteins

-ion channels + carriers

Plasma Membrane Specializations

Slide 3.8aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

MicrovilliFinger-like projections that increase surface area for absorption

Form is significant for functions of the small intestine and nephrons of kidney.

Figure 3.3

Cytoplasm

Slide 3.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

cytoplasm: fluid like substance outside the nucleus and inside the plasma membrane Has 2 parts:

∙Cytosol: fluid that suspends other elements

∙Organelles: “metabolic machinery” of the cell = each with unique form&function

Cytoplasmic Organelles

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Figure 3.4

Cytoplasmic Organelles

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∙ Ribosomes∙Made of protein and RNA

∙Sites of protein synthesis

∙Can be free in cytoplasm or attached to rER.

Endoplasmic Reticulum (ER)

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∙ Fluid-filled tubules ∙ Two types of

1. Rough ER∙ Studded with ribosomes∙ Site where building materials of cellular membrane are formed

2. Smooth ER∙ Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs

Rough ER: close to nucleus and has a lot of ribosomes.

Smooth ER: continuous with rER, but no ribosomes!

Golgi Apparatus

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∙ Golgi apparatus∙Modifies and packages proteins∙Ships out proteins to where they need to go.

Cytoplasmic Organelles

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Figure 3.5

Hydrolytic Organelles

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1. LysosomesHas enzymes that digest nonusable materials2. PeroxisomesContains enzymesDetoxify harmful substances (often producing hydrogen peroxide in the process.)

Cytoplasmic Organelles

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∙ Mitochondria∙ “Powerhouses” of the cell

∙ break down food (using oxygen) to produce ATP!

Cytoskeleton Network

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∙protein structures that allow for support and movement within the cell.

∙Three different types1. Microfilaments2. Intermediate

filaments3. Microtubules

Cell Diversity

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Figure 3.7; 1, 2

Cell Diversity

Slide 3.19bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.7; 3

Cell Diversity

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Figure 3.7; 4, 5

Cell Diversity

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Figure 3.7; 6, 7

Cell Membrane:made out of phospholipids arranged in a bilayer.

It is full of many other molecules as well….

Plasma Membrane

Slide 3.7bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.2

Membrane Videos: Passive process (simple/facilitated diffusion) (5m): https://www.youtube.com/watch?v=JShwXBWGMyY

Active transport: https://www.youtube.com/watch?v=owEgqrq51zY

Insulin in the human body (1.5): https://www.youtube.com/watch?v=OYH1deu7-4E

Membrane and Transport

Slide 3.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

movement of substance into and out of the cellselectively permeable : “controls” what gets in and out.

Two types of:∙Passive transport: no energy is required∙Active transport: requires energy

Passive Transport Processes

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Diffusion-Simple-Facilitated

Osmosis

Figure 3.8

Active Transport Processes

Slide 3.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Active Transport

Transport in Vesicles-Endocytosis-Exocytosis

p57

Figure 3.8

Passive Transport Processes

Slide 3.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

DiffusionParticles distribute in a solution

∙Movement is from high to low concentration

-(down a concentration gradient)

Figure 3.8

Passive Transport Processes

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Osmosis: simple diffusion of water through a membrane

Water moves toward high concentrations of solutes.

∙Your bodily fluids work to make sure the intracellular and interstitial fluids are equal to prevent a net movement of water into or out of the cell = BAD!

The net movement of H2O into and out of the cell should be equal.

Facilitated Diffusion: molecules are very large, must be “helped” through the membrane.∙Membrane proteins allow for the passage of these molecules (like glucose).

Diffusion through the Plasma Membrane

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Figure 3.9

Active Transport Processes

Slide 3.27Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Transport molecules using energy! Why?∙ They are too big∙ Polarity differences (membrane = polar and nonpolar sections you must get through).

∙ They are going against the concentration gradient

Two common forms:1. Protein channels (solute pumping)2. Endo- and Exocytosis (bulk transport)

Solute Pumping

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Proteins “pump” substances into the cell such as:

- Amino acids- Sugars - Ions

ATP (energy) required because it goes against the gradient.

Active Transport Processes

Slide 3.28bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.10

Active Transport Movie: https://www.youtube.

com/watch?v=owEgqrq51zY

Slide 3.29aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

moves “a lot” of stuff!Types of bulk transport:

1. Exocytosis = (Exit)∙ Moves materials out of the cell in a membranous vesicle

∙ Vesicle migrates to plasma membrane∙ Vesicle combines with plasma membrane∙ Material is emptied to the outside

Bulk transport

Active Transport Processes - Vesicles

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Figure 3.11

Slide 3.30aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. Endocytosis = (endo = in)Extracellular substances are enclosed in a membranous vesicle and “swallowed”.

-Types of endocytosis∙Phagocytosis – cell eating∙Pinocytosis – cell drinking

Active Transport Processes

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Figure 3.12

Phagocytosis vs. Pinocytosis

Slide 3.30bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.12

Phagocytosis vs. Pinocytosis

Slide 3.30bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 3.12

Endo and Exocytosis movie: https://www.youtube.com/watch?v=owEgqrq51zY

Cell Life Cycle

Slide 3.31Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

1. Interphase∙ Cell grows and does its job

∙ Some cells stay in interphase forever, others go on to divide.

∙ If the cell will divide, the DNA will “copy” itself = DNA replication

2. Mitosis (Cell division)∙ Cell replicates itself∙ Function is to produce more cells for growth and repair processes

Cellular Divisions: Mitosis

Slide 3.33Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Two Subdivisions:2. Mitosis

∙ Nucleus divides into two.3. Cytokinesis

∙ Division of the cytoplasm∙ Begins when mitosis is near completion∙ Results in the formation of two daughter cells- each an EXACT copy of the previous cell, except half the size!

Mitosis Video- Image of PMAT structure: bit.ly/1owVTee

METAPHASE

INTERPHASE

TELOPHASE

ANAPHASE

PROPHASE

Mitosis: The Anatomy version

Slide 3.37Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Regulation:Regulating the cell cycle is very important to the human body!

∙ Not all cells divide! Ex. = Neurons

Pace is important, too...cells dividing to quickly?

CANCER = second leading cause of death in US!

Protein Synthesis:

Slide 3.37Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Gene = DNA segment that carries a blueprint for building specific proteinsProteins have many functions

∙Ex. Building materials for cells∙Ex. Act as enzymes (biological catalysts)

RNA is essential for protein synthesis∙ DNA to RNA to Proteins!

Mutations….• Mutations = accidental changes in the

genetic code.• Types:

1. Chromosomal Mutations•Effect entire chromosomes

2. Point Mutations•Effect genes

How do such small mutations affect cells?

Because if you change the DNA…..

You change the mRNA…..

You change the tRNA…..

If that = a different amino acid = a PROBLEM!

Things to remember about Mutation:Not all mutations causes problems!

• Mutations in not in genes DNA- who cares?•Mutations that code for the same, or chemically similar amino acid- who cares?•Sometimes these are called silent mutations.

Some mutations are good!• Without mutations our DNA couldn’t change = no more evolution.• Some mutations may make a protein more efficient at its job, or have “hidden” positive effects.

What can cause mutations?• Genetics: you inherit them as errors in meiosis (egg and sperm)• DNA replication = doesn’t copy correctly

• Environment: UV radiation, radiation, aging process (free radicals in body)•Drugs and Chemicals

•Mutagens: known to cause mutations•Carcinogens: known to cause cancerous mutations•Teratogens: cause mutations in developing baby.

•Random errors…woops