Elsevier items and derived items © 2007, 2003, 2000 by Saunders, an imprint of Elsevier Inc. Slide 1

Chapter 3Cells

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A Typical Cell• The cell is the structural and functional unit of

all living matter.

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A Typical Cell - cont’d

• Cell Membrane (Plasma Membrane)– The cell membrane is composed of a two-layer

phospholipid and protein. – The cell membrane is selectively permeable.

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A Typical Cell - cont’d

• Structures Inside the Cell– The nucleus is the control center of the cell; it

stores the genetic information.– The cytoplasm is a gel-like substance inside the

cell membrane but outside of the nucleus.– Many different organelles are in the cytoplasm.– The mitochondria are the power plants of the cell.– Ribosomes are concerned with protein synthesis.

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A Typical Cell - cont’d

• Structures Inside the Cell—cont’d– The Golgi apparatus packages and puts the

finishing touches on the newly synthesized protein.

– Lysosomes act as intracellular housekeepers.– The cytoskeleton provides shape and support to

the cell.– Centrioles play a role in cell reproduction.

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A Typical Cell - cont’d

• Structures on the Cell Membrane– Cilia are short, hairlike projections.– Flagella are long, hairlike projections; the sperm

has a flagellum that allows it to swim.

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Movement Across the Cell Membrane• Passive Transport Mechanisms– Passive transport mechanisms require no input of

energy (ATP).– Diffusion is the movement of a substance from an

area of greater concentration to an area of lesser concentration.

– Facilitated diffusion is the same as diffusion but uses a helper molecule to increase the rate of diffusion.

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Movement Across the Cell Membrane - cont’d

• Passive Transport Mechanisms—cont’d– Osmosis is a special case of diffusion using a

semipermeable membrane. Osmosis involves the diffusion of water from an area with more water to an area of less water. The concentrations of a solution are expressed as tonicity. Solutions are isotonic, hypotonic, or hypertonic.

– Filtration is the movement of water and dissolved substances from an area of high pressure to an area of low pressure.

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• Active Transport Mechanisms– Active transport requires an input of energy (ATP).– Active transport pumps move substances from an

area of low concentration to an area of high concentration.

– Endocytosis moves substances into a cell; pinocytosis is cellular “drinking,” and phagocytosis is cellular “eating.”

– Exocytosis moves substances out of a cell.

Movement Across the Cell Membrane - cont’d

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Cell Division• Mitosis: produces two identical cells• Meiosis: occurs only in sex cells

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Cell Cycle• Interphase (G1, S, and G2 phases) • Mitosis (M phase)– The splitting of one mother cell into two

identical daughter cells.– Four phases of mitosis: prophase, metaphase,

anaphase, and telophase.• Cell Cycle–Phase Specific Drugs– Some drugs are aimed at a specific phase of

the cell cycle.– Some are cell cycle–phase nonspecific.

Elsevier items and derived items © 2007, 2003, 2000 by Saunders, an imprint of Elsevier Inc. Slide 12

Cell Differentiation

Elsevier items and derived items © 2007, 2003, 2000 by Saunders, an imprint of Elsevier Inc. Slide 13

Stem Cells

Elsevier items and derived items © 2007, 2003, 2000 by Saunders, an imprint of Elsevier Inc. Slide 14

Order, Disorder, and Death

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Introduction • Our bodies are made of different chemicals.

To understand the body, you need to understand some general chemical principles.

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Matter, Elements, and Atoms• Matter– Matter is anything that occupies space and has

weight. – Matter exists in three states: solid, liquid, and gas.– Matter can undergo physical and chemical changes.

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Matter, Elements, and Atoms - cont’d

• Elements– An element is a fundamental substance that

cannot be broken down into a simpler form by ordinary chemical means.

– Four elements (carbon, hydrogen, oxygen, and nitrogen) make up 96% of the body weight.

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Matter, Elements, and Atoms - cont’d

• Atoms– An atom is the basic unit of matter.– An atom is composed of three subatomic

particles: neutrons, protons, and electrons.– The atomic number: the number of protons.– The atomic weight: the number of neutrons

and protons.– An isotope is an atom with the same

atomic number but a different atomic weight. A radioisotope is an unstable isotope.

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Chemical Bonds• Electron Shells and Bonding– Each electron shell holds a specific number

of electrons. – Ionic bonds are formed as electrons are

transferred to stabilize the shells of the atoms.– Covalent bonds are formed as the electrons of the

outer shells are shared by the interacting atoms.– Hydrogen bonds are intermolecular bonds.

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Chemical Bonds - cont’d

• Ion Formation– An ion is an atom that carries an electrical charge.

A cation is a positively charged ion. An anion is a negatively charged ion.

– An electrolyte is a substance that forms ions when dissolved in water.

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Chemical Bonds - cont’d

• Molecules and Compounds– A molecule is a substance formed by two or more

atoms (O2, H2O).– A compound is a substance that forms when two

or more different atoms bond (H2O).– Important molecules and compounds include

water, oxygen, and carbon dioxide.

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Chemical Bonds - cont’d

• Acids and Bases– An acid is an electrolyte that dissociates into a

hydrogen ion (H+) and an anion.– A base is a substance that combines with H+ and

eliminates H+; a base neutralizes an acid by producing a salt and water.

– The pH scale measures acidity and alkalinity. A pH of 7 is neutral. A pH less than 7 is acidic, and a pH greater than 7 is basic, or alkaline.

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Chemical Bonds - cont’d

• Acids and Bases—cont’d– The normal pH of the blood is 7.35 to 7.45. A

person with a pH less than 7.35 is acidotic, and a person with a pH greater than 7.45 is alkalotic.

– Blood pH is regulated by buffers, the respiratory system, and the kidneys.

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Energy• Definition: the ability to do work.• Forms of Energy– The six forms of energy: see Table 2-3.– Most energy is released as heat.

• Role of Adenosine Triphosphate (ATP)– ATP is an energy-transfer molecule.– The energy is stored in high-energy phosphate

bonds.

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Mixtures, Solutions, and Suspensions• A mixture is a blend of two or more

substances that can be separated by ordinary physical means.

• Solutions, suspensions, and colloidal suspensions are types of mixtures.

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Chapter 1Introduction to the Human Body

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Introduction• Anatomy is the study of structure; physiology

is the study of function.

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The Body’s Levels of Organization• From Simple to Complex– The body is arranged from simple to complex.– Structure and function are related.

• Major Organ Systems– An organ system is a group of organs that help

each other to perform a particular function.

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The Body’s Levels of Organization - cont’d

• Major Organ Systems – There are 11 major organ systems.• The integumentary system • The skeletal system • The muscular system • The nervous system • The endocrine system • The circulatory system • The lymphatic system

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The Body’s Levels of Organization - cont’d

• Major Organ Systems – There are 11 major organ systems—cont’d.

• The respiratory system • The digestive system • The urinary system • The reproductive system

– Homeostasis refers to the body’s ability to maintain a stable internal environment in response to a changing external environment

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Anatomical Terms: Talking About the Body

• Anatomical Position– The anatomical position is the body standing erect,

arms by the side, with palms facing forward.– Paired terms that describe direction include superior

and inferior, anterior and posterior, medial and lateral, proximal and distal, superficial and deep, and central and peripheral.

– The three planes are the sagittal plane, frontal (coronal) plane, and transverse plane.

– Regional terms are listed in Figure 1-6.

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Anatomical Terms: Talking About the Body - cont’d

• Cavities of the Body– Dorsal cavity• The cranial cavity contains the brain.• The spinal cavity, or vertebral cavity, contains

the spinal cord.

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Anatomical Terms: Talking About the Body - cont’d

– Ventral Cavity• The thoracic cavity is above the diaphragm and contains

the lungs; it also contains the mediastinum. • The abdominopelvic cavity is located below the

diaphragm.– The abdominal cavity is the upper part that contains the

stomach, most of the intestines, liver, spleen, and kidneys.– The pelvic cavity is the lower part that contains the reproductive

organs, urinary bladder, and lower part of the intestines.• For reference, the abdominopelvic cavity is divided into

four quadrants and nine regions.