Chapter 1Introduction to Human Anatomy and Physiology

Anatomy and Physiology

Anatomy deals with the structure (morphology) of the body and its parts, in other words, what are things called? Physiology studies the functions of these parts or asks the question, how do they work?

The two disciplines are closely interrelated because the functional role of a part depends on how it is constructed.

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Maintenance of a stable internal environment is called homeostasis. Homeostasis is regulated through control systems which have receptors, a set point and effectors in common. Examples include:a. Homeostatic mechanisms regulate body temperature in a manner similar to the functioning of a home heating thermostat.b.Another homeostatic mechanism employs pressure-sensitive receptors to regulate blood pressure. Homeostasis:

Many of the body's homeostatic controls are negative feedback mechanisms. Each individual uses homeostatic mechanisms to keep body levels within a normal range; normal ranges can vary from one individual to the next.

Homeostasis:

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1.Atoms are the simplest level.2.Two or more atoms comprise a molecule.3.Macromolecules are large, biologically important molecules inside cells.4.Organelles are aggregates of macromolecules used to carry out a specific function in the cell.5.Cells are the basic living unit.6.Tissues are groups of cells functioning together.7.Groups of tissues form organs.8.Groups of organs function together as organ systems.9.Organ systems functioning together make up an organism. The human body is the sum of its parts and these parts can be studied at a variety of levels of organization.

Organization of the Human Body

Major features of the human body include its cavities, membranes, and organ systems.

Body Cavities:The body can be divided into an appendicular portion (upper and lower limbs) and an axial portion (head, neck, and trunk), which includes a dorsal and a ventral cavity. Organs within these cavities are called viscera.

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a.The dorsal cavity can be divided into the cranial cavity and vertebral canal.b.The ventral cavity is made up of a thoracic cavity and an abdominopelvic cavity, separated by the diaphragm.i.The mediastinum divides the thorax into right and left halves.ii.The abdominopelvic cavity can be divided into the abdominal cavity and the pelvic cavity.c.Smaller cavities within the head include the oral cavity, nasal cavity, orbital cavities, and middle ear cavities.

Thoracic and Abdominopelvic Serousal Membranes:

1.The thoracic cavity is lined with pleura; the parietal pleura lines the cavities while the visceral pleura covers the lungs. A thin layer of serous fluid separates the two layers.2.The heart is surrounded by pericardium. The visceral pericardium covers the heart and the parietal pericardium makes up an outer sac. Serous fluid separates the two layers.3.Peritoneum lines the abdominopelvic cavity; a parietal peritoneum lines the wall while visceral peritoneum covers the organs.

Organ Systems: Body Covering a.The integumentary system, including skin, hair, nails, and various glands, covers the body, senses changes outside the body, and helps regulate body temperature.

Support and Movement a.The skeletal system, made up of bones and ligaments. It supports, protects, provides frameworks, stores inorganic salts, and houses blood-forming tissues.b.The muscular system consists of the muscles that provide body movement, posture, and body heat.

Integration and Coordinationa.The nervous system consists of the brain, spinal cord, nerves, and sense organs. It integrates information incoming information from receptors and sends impulses to muscles and glands.b.The endocrine system, including all of the glands that secrete hormones, helps to integrate metabolic functions

Transport a.The cardiovascular system, made up of the heart and blood vessels, distributes oxygen and nutrients throughout the body while removing wastes from the cells.b.The lymphatic system, consisting of lymphatic vessels, lymph nodes, thymus, and spleen, drains excess tissue fluid and includes cells of immunity.

Absorption and Excretion a.The digestive system is made up of the mouth, esophagus, stomach, intestines and accessory organs. It receives, breaks down, and absorbs nutrients.b.The respiratory system exchanges gases between the blood and air and is made up of the lungs and passageways.c.The urinary system, consisting of the kidneys, ureters, bladder, and urethra, removes wastes from the blood and helps to maintain water and electrolyte balance.

Reproduction a.The reproductive system produces new organisms.i.The male reproductive system consists of the testes, accessory organs, and vessels that conduct sperm to the penis.ii.The female reproductive system consists of ovaries, uterine tubes, uterus, vagina, and external genitalia. The female reproductive system also houses the developing offspring.

Anatomical Terminology Relative Positions:1.Terms of relative position are used to describe the location of a part relative to another part.2.Terms of relative position include: superior, inferior, anterior, posterior, medial, lateral, proximal, distal, superficial (peripheral), and deep.

Body Sections:1.A sagittal section divides the body into right and left portions.2.A transverse section divides the body into superior and inferior portions. It is often called a cross section.3.A coronal section divides the body into anterior and posterior sections.

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Body Regions 1.The abdominal area can be divided into nine regions.2.Terms used to refer to various body regions are depicted in Fig. 1.13.CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 2

Chemical Basis of Life

Introduction: A.Chemistry deals with the composition of substances and how they change.B.A knowledge of chemistry is necessary for the understanding of physiology because of the importance of chemicals in body processes.

A.Elements and Atoms:

Matter is anything that takes up space.

All matter is composed of elements, 92 of which occur naturally.

Living organisms require about 20 elements, of which oxygen, carbon, hydrogen, and nitrogen are most abundant.

Elements are composed of atoms; atoms of different elements vary in size and in how they interact.

Structure of Matter:

B.Atomic Structure: 1.An atom consists of a nucleus containing protons and neutrons, with electrons in orbit around the nucleus in shells.2.Protons, with a positive charge, are about equal in size to neutrons, which have no charge.

C.Bonding of Atoms: 1.Atoms form bonds by gaining, losing, or sharing electrons.2.Electrons are found in shells around the nucleus.a. The first energy shell holds two electrons; the other energy shells each hold eight electrons when on the outside.

C.Bonding of Atoms:3.Atoms with incompletely filled outer shells tend to be reactive to form stable outer shells of 8.When atoms gain or lose electrons, they become ions with a charge. Whether they gain or lose will depend on how many they have in the outer shell to start with.

5.Oppositely-charged ions attract each other and form an ionic bond.

1.Covalent bonds are formed when atoms share electrons to become stable with filled outer shells.a.Two pairs of electrons shared between atoms form a double covalent bond. D.Covalent Bond:

1. A molecular formula represents the numbers and types of atoms in a molecule.

2. Various representations, called structural formulas, can be used to illustrate molecules.

E.Formulas:

Chemical ReactionsH2O + CO2 > HCO3- +H+

1.A chemical reaction occurs as bonds are formed or broken between atoms, ions, or molecules.2.Those changed by the reaction are the reactants; those formed are the products.3.Two or more atoms or molecules can be joined during synthesis.4.Larger molecules can be broken into smaller ones indecomposition reactions.5.Exchange reactions occur as parts of molecules trade places.6.Reversible reactions are symbolized by using two arrows.7.Catalysts influence the rates of chemical reactions.

F.Chemical Reactions:

1.Substances that release ions in water are called electrolytes.

2.Electrolytes that release hydrogen ions in water are called acids.

3.Electrolytes that release ions that combine with hydrogen ions in water are called bases.

G.Acids and Bases:

G.Acids and Bases:4.The concentrations of H+ & OH- in the body is very important to physiology.

5.pH represents the concentration of hydrogen ions [H+] in solution.

A. Compounds that contain both hydrogen and carbon are called organic, the others are inorganic

Chemical Constituents of Cells:

1.Water

a.Water is the most abundant compound in living things and makes up two-thirds of the weight of adults.

b.Water is an important solvent so most metabolic reactions occur in water.

B.Inorganic Substances

2.Oxygen a.Oxygen is needed to release energy from nutrients and is used to drive the cell's metabolism.3.Carbon Dioxidea.Carbon dioxide is released as a waste product during energy-releasing metabolic reactions.

B.Inorganic Substances

4.Inorganic Salts a.Inorganic salts are the sources of ions of sodium, chloride, potassium, calcium, magnesium, phosphate, carbonate, bicarbonate, and sulfate.b.These electrolytes play important roles in many of the body's metabolic processes. B.Inorganic Substances

1.Carbohydrates a.Carbohydrates provide energy for cellular activities and are composed of carbon, hydrogen, and oxygen.b.Carbohydrates are made from monosaccharides (simple sugars); disaccharides are two monosaccharides joined together; complex carbohydrates (polysaccharides), such as starch, are built of many sugars.

C.Organic Substances:

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a.Lipids are insoluble in water and include fats, phospholipids, and steroids.b.Fats supply energy, are composed of oxygen, carbon, and hydrogen, and are built from glycerol and three fatty acids.

2.Lipids:

c.Phospholipids contain glycerol, two fatty acids, and a phosphate group, and are important in cell structures.d.Steroids are complex ring structures, and include cholesterol, which is used to synthesize the sex hormones.

2.Lipids:

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a.Proteins have a great variety of functions in the body---as structural materials, as energy sources, as certain hormones, as receptors on cell membranes, as antibodies, and as enzymes to catalyze metabolic reactions.

3.Proteins:

b.Proteins contain C, O, H, and nitrogen atoms; some also contain sulfur.c.Building blocks of proteins are the amino acids, each of which has a carboxyl group, an amino group and a side chain called the R group.

3.Proteins:

d.Proteins have complex shapes held together by hydrogen bonds.e.Protein shapes, which determine how proteins function, can be altered (denatured) by pH, temperature, radiation, or chemicals.

3.Proteins:

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a.Nucleic acids form genes and take part protein synthesis.b.They contain carbon, hydrogen, oxygen, nitrogen, and phosphorus, which are bound into building blocks called nucleotides.

4.Nucleic Acids:

c.Nucleic acids are of two major types: DNA (with deoxyribose) and RNA (with ribose).d.RNA (ribonucleic acid) functions in protein synthesis; DNA (deoxyribonucleic acid) stores the molecular code in genes.

4.Nucleic Acids:

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Chapter 3Cells

A.The human body consists of 75 trillion cells that vary considerably in shape and size yet have much in common.B.Differences in cell shape make different functions possible.

Introduction:

A.A composite cell includes many different cell structures.B.A cell consists of three main parts---the nucleus, the cytoplasm, and the cell membrane.C.Within the cytoplasm are specialized organelles that perform specific functions for the cell.

A Composite Cell:

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1.The cell membrane regulates the movement of substances in and out of the cell, participates in signaltransduction, and helps cells adhere to other cells.

D. Cell Membrane:

2.General Characteristics a.The cell membrane is extremely thin and selectively permeable.b.It has a complex surface with adaptations to increase surface area.

D. Cell Membrane:

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3.Cell Membrane Structure: a.The basic framework of the cell membrane consists of a double layer of phospholipids, with fatty acid tails turned inward.b.Molecules that are soluble in lipids (gases, steroid hormones) can pass through the lipid bilayer.

D. Cell Membrane:

c.Embedded cholesterol molecules strengthen the membrane and help make the membrane less permeable to water-soluble substances.d.Many types of proteins are found in the cell membrane, including transmembrane proteins and peripheral membrane proteins.

D. Cell Membrane:

e.Membrane proteins perform a variety of functions and vary in shape.

f.Some proteins function as receptors on the cell surface, starting signal transduction.

g.Other proteins aid the passage of molecules and ions.

D. Cell Membrane:

h.Proteins protruding into the cell anchor supportive rods and tubules.

i.Still other proteins have carbohydrates attached; these complexes are used in cell identification. Membrane proteins called cellular adhesion molecules (CAMs) help determine one cells interactions with others.

D. Cell Membrane:

1.The cytoplasm consists of a clear liquid (cytosol), a supportive cytoskeleton, and networks of membranes and organelles. a.Endoplasmic reticulum is made up of membranes, flattened sacs, and vesicles, and provides a tubular transport system inside the cell. E. Cytoplasm:

1a1.With ribosomes, endoplasmic reticulum (ER) is rough ER, and functions in protein synthesis.

1a2.Without ribosomes, it is smooth ER, and functions in lipid synthesis.E. Cytoplasm: (cont.)

b.Ribosomes are found with ER and are scattered throughout the cytoplasm. They are composed of protein and RNA and provide a structural support for the RNA molecules that come together in protein synthesis.E. Cytoplasm: (cont.)

d.Mitochondria are the powerhouses of the cell and contain enzymes needed for aerobic respiration.i.The inner membrane of the mitochondrion is folded into cristae which hold the enzymes needed in energy transformations to make ATP.ii.Very active cells contain thousands of mitochondria.E. Cytoplasm: (cont.)

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e.Lysosomes are the "garbage disposals" of the cell and contain digestive enzymes to break up old cell components and bacteria.f.Peroxisomes contain enzymes that function in the synthesis of bile acids, breakdown of lipids, degradation of rare biochemicals, and detoxification of alcohol. E. Cytoplasm: (cont.)

F.Cell Nucleus:1.The fairly large nucleus is bounded by a double-layered nuclear membrane containing relatively large nuclear pores that allow the passage of certain substances.E. Cytoplasm: (cont.)

A.The cell membrane controls what passes through it.

Mechanisms of movement across the membrane may be passive, requiring no energy from the cell (diffusion, facilitated diffusion, osmosis, and filtration) or active mechanisms, requiring cellular energy (active transport, endocytosis, and exocytosis).

Movements Through Cell Membranes

C.Passive Mechanisms 1.Diffusion a.Diffusion is caused by the random motion of molecules and involves the movement of molecules from an area of greater concentration to one of lesser concentration until equilibrium is reached.

Movements Through Cell Membranes (cont.)

C1b.Diffusion enables oxygen and carbon dioxide molecules to be exchanged between the air and the blood in the lungs, and between blood and tissue cells.

Movements Through Cell Membranes (cont.)

C2.Facilitated Diffusiona.Facilitated diffusion uses membrane proteins that function as carriers to move molecules (such as glucose) across the cell membrane.b.The number of carrier molecules in the cell membrane limits the rate of this process.

Movements Through Cell Membranes

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C3.Osmosis a.Osmosis is a special case of diffusion in which water moves from an area of greater water concentration (where there is less osmotic pressure) across a selectively permeable membrane to an area of lower water concentration (where there is greater osmotic pressure).

Movements Through Cell Membranes

A solution with the same osmotic pressure as body fluids is called isotonic; one with higher osmotic pressure than body fluids is hypertonic; one with lower osmotic pressure is hypotonic.

Movements Through Cell Membranes

C4.Filtration a.Because of hydrostatic pressure, molecules can be forced through membranes by the process of filtration. Blood pressure is a type of hydrostatic pressure.

Movements Through Cell Membranes

D.Active Mechanisms1.Active Transport a.Active transport uses ATP to move molecules from areas of low concentration to areas of high concentration through carrier molecules in cell membranes.b.As much as 40% of a cell's energy supply may be used to fuel this process.Movements Through Cell Membranes

D1c.The union of the specific particle to be transported with its carrier protein triggers the release of cellular energy (ATP), which in turn alters the shape of the carrier protein, releasing the particle to the other side of the membrane.Movements Through Cell Membranes (cont.)

D1d.Particles that are actively transported include sugars, amino acids, and sodium, potassium, calcium, and hydrogen ions, as well as nutrient molecules in the intestines.

Movements Through Cell Membranes (cont.)

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D2. Endocytosis and Exocytosis

a.In endocytosis, molecules that are too large to be transported by other means are engulfed by an invagination of the cell membrane and carried into the cell surrounded by a vesicle.b.Exocytosis is the reverse of endocytosis.Movements Through Cell Membranes (cont.)

D2c.Three forms of endocytosis are pinocytosis, phagocytosis, and receptor-mediated endocytosis.i.Pinocytosis is a form of endocytosis in which cells engulf liquids.ii.Phagocytosis is a form of endocytosis in which the cell takes in larger particles, such as a white blood cell engulfing a bacterium.iii.Receptor-mediated endocytosis allows the cell to take in very specific molecules (ligands) that pair up with specific receptors on the cell surface.

Movements Through Cell Membranes (cont.)

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G.Cell Differentiation

1. The process by which cells develop into different types of cells with specialized functions is called differentiation.

2. Cell differentiation reflects genetic control of the nucleus as certain genes are turned on while others are turned off.

Cell Differentiation