New Terminology and Related Clinical Terminology—These are some of the new terms you will encounter in the chapter. If not, the questions can be used as a self-test to evaluate your understanding of the chapter's content.
Acknowledgments
Contents
An Introduction to Microbiology
C Normal values for some commonly used blood tests, 532 D Normal values for some commonly used urine tests, 533 E Eponymous terms, 534.
Organization and General Plan of the Body
Name the levels of body organization from simplest to most complex and explain each. All cells in the body must receive oxygen in order to function properly, so the physiology of red blood cells is essential to the physiology of the body as a whole.
LEVELS OF ORGANIZATION
Levels of structural organization of the human body, depicted from the simplest (chemical) to the most complex (organism). 1-1 you see the urinary system, which consists of the kidneys, ureters, urinary bladder and urethra.
METABOLISM AND HOMEOSTASIS
This is an example of a negative feedback mechanism, in which the body's response reverses the stimulus (in effect, turns it off for a while) and keeps some aspect of the body's metabolism within its normal range. 1–3 for another negative feedback mechanism, one in which the hormone thyroxine regulates the metabolic rate of the body.
TERMINOLOGY AND GENERAL PLAN OF THE BODY
The pelvic cavity can be considered a subdivision of the abdominal cavity (there is no wall between them) or as a separate cavity. The membranes of the abdominal cavity are also serous membranes called the peritoneum and mesentery.
SUMMARY
STUDY OUTLINE
Metabolism is the sum of all the chemical and physical changes that occur in the body. Abdominal cavity - the diaphragm separates the thoracic and abdominal cavities; the pelvic cavity is inferior to the abdominal cavity.
REVIEW QUESTIONS
Homeostasis is a state of good health maintained by the normal metabolism (functioning) of organ systems. Describe two of these differences and explain how they relate to the physiology of the hand and foot.
Some Basic Chemistry
Recall from Chapter 1 that the simplest level of body organization is the chemical level. This chapter covers some very basic aspects of chemistry as they relate to living organisms, and especially as they relate to our understanding of the human body.
ELEMENTS
When you hear or see the word chemistry, you might think of test tubes and Bunsen burners in a lab experiment. So try not to think of chemistry as a complicated science, but as the air, water and food we need, and every substance that makes up us.
ATOMS
This ability depends on the number and arrangement of the atom's electrons. By doing so, an atom is able to form one or more chemical bonds with others.
CHEMICAL BONDS
Together they form a molecule of oxygen gas (O2), which is the form in which oxygen is found in the atmosphere. An oxygen atom can also share two of its electrons with two hydrogen atoms, each sharing its single electron (see Fig. 2-3).
CHEMICAL REACTIONS
Hydrogen bonds also make water cohesive; that is, each water molecule is attracted to nearby water molecules. These hydrogen bonds are also responsible for other important characteristics of water, discussed in the next section.
INORGANIC COMPOUNDS OF IMPORTANCE
Extracellular Fluid (ECF) - all the rest of the water in the body; about 35% of the total. Each of the four products of this process has a purpose or meaning in the body.
ORGANIC COMPOUNDS OF IMPORTANCE
Lecithin is a phospholipid that is part of our cell membranes (see Fig. 3-1; each phospholipid molecule looks like a sphere with two tails; .. the sphere is glycerol and phosphate, the tails are the two fatty acids) . This is why a state of acidosis can cause cell death - the cells' enzymes are unable to function properly.
Cells
All the evidence that science has accumulated so far supports the validity of the cell theory. Most human cells are so small that they can only be seen with the aid of a microscope and are measured in units called micrometers (formerly called microns).
CELL STRUCTURE
Remember from our earlier discussion that DNA is the genetic code for the cell's characteristics and activities. As a network of interconnected tunnels, the ER is a passageway for the transport of materials necessary for cell function within the cell.
CELLULAR TRANSPORT MECHANISMS
The movement of molecules from an area of greater concentration to an area of lesser concentration. Movement of molecules from an area of less concentration to an area of greater concentration (requires ATP).
THE GENETIC CODE
The blood pressure in capillaries is higher than the pressure of the surrounding tissue fluid. The white blood cell flows around the bacterium (see Fig. 3–3), ingesting it and finally digesting it.
AND PROTEIN SYNTHESIS
The mRNA is formed as a copy of part of the DNA in the nucleus of a cell. There is a triplet of bases in DNA for each amino acid in the protein.
CELL DIVISION
Meiosis is a more complex process of cell division that results in the formation of gametes, which are egg and sperm cells. The new cells fill in the damaged area and mitosis slows down as the cells make contact with surrounding cells.
AGING AND CELLS
Facilitated diffusion – transporters (transfer enzymes) that are part of the cell membrane allow cells to take in materials that would not diffuse. Cells of the small intestine absorb glucose and amino acids from digested food by active transport.
Tissues and Membranes
Describe the functions of epithelial tissue types in relation to the organs in which they are found. Tissue contributes to the functioning of the organs in which it is located.
EPITHELIAL TISSUE
This type of epithelium forms the epidermis of the skin, where it is called. As mentioned earlier, goblet cells are found in the lining of the respiratory tract and digestive tract.
CONNECTIVE TISSUE
The strong outer wall prevents the artery from rupturing (see also Box 4–2: Vitamin C and Collagen). An irregular type of fibrous connective tissue forms the dermis of the skin and the fasciae (membranes) around the muscles.
MUSCLE TISSUE
The wall of the trachea, the airway to the lungs, contains tough rings of cartilage that keep the passage of air open. The heart muscle as a whole is called the myocardium and forms the walls of the four chambers of the heart.
NERVE TISSUE
The cell membranes at the ends of these cells are somewhat folded and fit into matching folds of the membranes of the following cells. The contractions of the myocardium create blood pressure and keep blood circulating throughout the body, allowing the blood to perform its many functions.
MEMBRANES
These include sensing and interpreting sensation, initiating movement, rapidly regulating body functions such as heart rate and breathing, and organizing information for learning and memory. Serous membranes are found in closed body cavities, such as the thoracic and abdominal cavities.
AGING AND TISSUES
Locations: bones of the skeleton (to support the body and protect internal organs from mechanical damage). Name the two main layers of the skin and the tissue each is made of.
The Integumentary System
The integrative system consists of the skin, its accessory structures such as hair and sweat glands, and the subcutaneous tissue beneath the skin. The subcutaneous tissue directly under the skin connects it to the muscles and has other functions.
THE SKIN
So sensation is actually a function of the brain (we'll come back to this in Chapters 8 and 9). In cold, the skin of the extremities may become even paler as blood flow through the dermis decreases.
SUBCUTANEOUS TISSUE
The name is a bit misleading, because the most difficult part of cutaneous absorption of a drug is absorption through the stratum corneum of the epidermis. Subcutaneous adipose tissue has a moderate blood supply, so the absorption rate of the drug will be moderate, but predictable.
AGING AND THE
INTEGUMENTARY SYSTEM
Vasoconstriction in cold temperatures reduces dermal blood flow to conserve heat in the body's core. Describe the functions of the skull, vertebral column, thorax, scapula, and pelvis.
The Skeletal System
Such an image is accurate and reflects the most obvious function of the skeleton - to support the body. The skeletal system consists of bones and other structures that make up the joints of the skeleton.
FUNCTIONS OF THE SKELETON
Although it is a framework for the body, the skeleton is nothing like the wooden beams that support a house. Bones are living organs that actively contribute to the maintenance of the body's internal environment.
TYPES OF BONE TISSUE
CLASSIFICATION OF BONES
The periosteum anchors these structures and contains both the blood vessels that enter the bone itself and osteoblasts that become active if the bone is damaged.
EMBRYONIC GROWTH OF BONE
FACTORS THAT AFFECT BONE GROWTH AND MAINTENANCE
Simple (closed)—the fractured parts are still in normal anatomical position; surrounding tissue damage is minimal (skin is not punctured). Bumped—the broken ends of a bone are forced together; many bone fragments can be created.
THE SKELETON
In the maxillae and lower jaw are sockets for the roots of the teeth. The thoracic vertebrae articulate (form joints) with the ribs at the back of the trunk.
JOINTS—ARTICULATIONS
AGING AND THE SKELETAL SYSTEM
Osteoclasts form the marrow cavity by reabsorbing the bone matrix in the center of the diaphysis (see Fig. 6-3). Name the bones that make up the rib cage and describe two functions of the rib cage.
The Muscular System
Aging and the Muscular System Major Muscles of the Body Muscles of the Head and Neck Muscles of the Trunk. The grace and coordination involved in dance is the result of the interaction of many organ systems, but the one that comes to mind first is probably the muscular system.
MUSCLE STRUCTURE
Flexion of the arm (across the chest) is also a function of the pectoralis major and extension of the arm (behind the back) is also a function of the latissimus dorsi. When the hand is palm facing up, the biceps do most of the bending work and can be called the driving force.
MUSCLE TONE
During walking, for example, the antagonistic muscles in the front and back of the thigh or in the lower part of the leg will alternate their contractions and relaxations and our steps will be smooth and efficient. Coordination occurs below the level of conscious thought and is regulated by the cerebellum, which is located below the occipital lobes of the brain.
MUSCLE SENSE
ENERGY SOURCES FOR MUSCLE CONTRACTION
Glucose is then further broken down in the process of cellular respiration to produce ATP and muscle fibers can continue to contract. Although the respiratory rate increases, the muscle fibers can literally run out of oxygen.
MUSCLE FIBER—
When glycogen is needed to provide energy for sustained contractions (more than a few seconds), it is first broken down into the glucose molecules from which it is made. Within muscle fibers themselves there is another protein called myoglobin, which stores oxygen in the muscle cells.
MICROSCOPIC STRUCTURE
Structure of the neuromuscular junction showing an axon terminal adjacent to the sarcolemma of a muscle fiber. By doing so, acetylcholine makes the sarcolemma highly permeable to Na⫹ ions, which rush into the cell.
CONTRACTION—THE SLIDING FILAMENT MECHANISM
Other disorders affecting muscle function are discussed in Box 7–3: Muscular dystrophy and Box 7–4: Myasthenia gravis.
RESPONSES TO EXERCISE—
MAINTAINING HOMEOSTASIS
The muscular dystrophy gene on the X chromosome was located, and the protein the gene codes for was named dystrophin. Dystrophin is necessary for the stability of the sarcolemma and the proper movement of ions.
AGING AND THE MUSCULAR SYSTEM
MAJOR MUSCLES OF THE BODY
The muscles that make up the largest part of the forearm are the flexors and extensors of the hand and fingers. Name all the muscles you can think of that move the thigh at the hip.
The Nervous System
Autonomic nervous system (AW-toh-NOM-ik) Cauda equina (KAW-dah ee-KWHY-nah) Cerebral cortex (see-REE-bruhl KOR-teks) Cerebrospinal fluid (see-REE-broh-SPY-nuhl) Choroid plexus ( KOR-oid PLEK-sus) Corpus callosum (KOR-pus kuh-LOH-sum) Cranial nerves (KRAY-nee-uhl NERVS) Efferent (EFF-uh-rent). The nervous system is one of the regulatory systems (the endocrine system is the other and is discussed in Chapter 10).
NERVOUS SYSTEM DIVISIONS
A chemical inactivator in the cell body or dendrite of a postsynaptic neuron rapidly inactivates the neurotransmitter. Multiple sclerosis (MS) is a demyelinating disease; that is, it involves the deterioration of the myelin sheath of neurons in the central nervous system.
TYPES OF NEURONS
Visceral motor neurons form the autonomic nervous system, a specialized subdivision of the PNS that will be discussed later in this chapter. This is the result of the neuron's structure and location, as well as its physical arrangement with other neurons and the resulting pattern of synapses.
NERVES AND NERVE TRACTS
The functioning nervous system is therefore a vast network of 'one-way streets' and there is no danger of impulses meeting and canceling each other out.
THE NERVE IMPULSE
THE SPINAL CORD
In the spinal cord, sensory neurons synapse with (4) motor neurons (this is a two-neuron reflex). However, if the reflex is normal, it means that all parts of the reflex arc are intact.
THE BRAIN
Most of us, when embarrassed, will blush, which is vasodilation in the skin of the face. For example, if the CVA is in the left frontal lobe, paralysis of the right half of the body occurs.
