3: Anatomy, Biochemistry, and Physiology

CHAPTER 3 Anatomy, Biochemistry, and Physiology

GENERAL ANATOMY

Anatomy is the study of structure; physiology is the study of function; gross anatomy is the study of the body’s structure that is visible with the naked eye; and microanatomy (histology) examines the cellular composition of tissues. Structures and associated functions are organized in interacting hierarchy from simple to complex (i.e., chemicals, cells, tissues, organs, body systems, total organism).

Organs of the body include integumentary, skeletal, muscular, nervous (including special sense organs), endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive. Knowing these systems can help you to understand a medical term. A term related to each of these systems might be augmented with roots, prefixes, and suffixes (see CD-ROM for commonly encountered ones), filling out the other two thirds of the term. If you know those, plus the name of the body system, you are well on your way to understanding another third or more of a term. In addition, anatomical nomenclature includes directional terms that describe relative position of body parts in anatomical position (see CD-ROM).

See Chapter 2, Embryology and Histology: cell structure.

Integumentary System

Integumentary system consists of skin (cutaneous membrane), including glands, hair, and nails (adnexa). Skin has outermost epidermis and innermost dermis anchored to underlying tissues by hypodermis or subcutaneous tissue; it is the largest external organ.

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Figure 3-1 Structure of the skin, with epidermis and dermis.

(From Bath-Balogh M, Fehrenbach MJ: Illustrated dental embryology, histology, and anatomy, ed 2, St. Louis, 2006, Saunders/Elsevier.)

Skeletal System

Skeletal system (206 bones) includes axial skeleton (80), forming axis of the body, and appendicular skeleton (126), consisting of appendages and attachments. System functions to provide support, protect soft body parts, produce movement with muscles, store minerals (calcium), form blood cells.

See Chapter 4, Head, Neck, and Dental Anatomy: skull, hyoid bone.
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Figure 3-2 Structure of bone tissue.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-3 Bones of the skeleton.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Muscular System

Muscular system includes skeletal muscle tissue that can be controlled voluntarily. Functions include moving the skeleton, maintaining posture, supporting soft tissues, producing heat to maintain body temperature.

See Chapter 4, Head, Neck, and Dental Anatomy: muscles.
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Figure 3-4 Structure of muscles.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-5 General view of body musculature. A, Anterior view. B, Posterior view.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Nervous System

Nervous system includes all neural tissue (neurons and neuroglia). The synapse is in the region of communication between neurons; communication occurs through the effects of neurotransmitters. Sensory nerves (dorsal root) transmit information to the brain and spinal cord. Motor nerves (ventral root) transmit information from the brain and spinal cord to effectors, such as muscles and glands. Integrative functions interpret the sensory information and act by stimulating motor pathways. Divided into central nervous system (CNS) and peripheral nervous system (PNS), which function together to integrate and coordinate body activities, assimilate experiences, and assist in memory and learning.

See Chapters 6, General and Oral Pathology: nervous system pathology; 9, Pharmacology: drugs and nervous system; 14, Pain Management: nerve anatomy and physiology.
A. CNS: composed of the brain and spinal cord (Figures 3-6 and 3-7):

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Figure 3-6 Brain.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-7 Brain and spinal cord.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Cranial Nerves

Cranial nerves are part of the PNS; designated by both number and Roman numerals I through XII, as well as specific name (Figure 3-8). Include 12 pairs that are connected to the brain at its base and pass through the skull by way of fissures and foramina; may be either afferent or efferent or have both types.

See Chapters 4, Head, Neck, and Dental Anatomy: fifth (trigeminal) and seventh (facial); 6, General and Oral Pathology, and 16, Special Needs Patient Care: neurological disorders.
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Figure 3-8 Cranial nerves.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Sense Organs

Sense organs include the widely distributed general senses and localized special senses of taste, smell, vision, hearing, equilibrium.

See Chapter 4, Head, Neck, and Dental Anatomy: lacrimal gland.
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Figure 3-9 Anatomy of the eye.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-10 External ear.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

CLINICAL STUDY

Age 68 YRS SCENARIO
Sex image Male image Female The dental hygienist calls to remind the patient that she is due for her 3-month recall appointment. The patient says that she has just been diagnosed with an eye disease that has permanently narrowed her fi eld of vision. She does not like the drops prescribed and wonders why she should take them.
Height 5′5″
Weight 145 LBS
BP 118/74
Chief Complaint “How am I going to get to the appointment?”
Medical History

Current Medications Ibuprofen p.r.n. Social History Retired grade school teacher

Endocrine System

Endocrine system consists of endocrine glands (release product into bloodstream) and hormones produced (Figure 3-11). Acts with nervous system to regulate body activities to maintain homeostasis. Nervous system acts through electrical impulses and uses a neurotransmitter, and effects are MORE localized and of LESS duration; endocrine system acts through a chemical messenger called a hormone, and effects are MORE generalized and of MORE duration.

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Figure 3-11 Endocrine glands.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Endocrine glands are ductless; secretions flow directly into blood, which carries the hormones to appropriate region (exocrine glands release product to the body surface). Exert effects on specific target organs by attaching to receptor sites, causing some type of reaction in organ.

Cardiovascular System

Cardiovascular system (CVS) includes blood, heart, and blood vessels.

See Chapters 8, Microbiology and Immunology: immunology of the blood; 9, Pharmacology: drugs that affect CVS.
A. Blood (liquid connective tissue):

B. Heart: muscle that pumps the blood, with two thirds on the left of the sternum; enclosed in fibrous pericardial sac lined with serous membrane (Figure 3-12):

Table 3-2 Known immunoglobulins (antibodies)

Immunoglobulin Description
IgA Has two subgroups: serous in blood and secretory in saliva and other secretions; aids in defense against proliferation of microorganisms in body fluids
IgE Involved in hypersensitivity reactions, since can bind to mast cells and basophils and bring about release of bioactive substances such as histamine
IgD Functions in activation of B-cell lymphocytes.
IgG Major antibody in blood serum; can pass placental barrier and forms first passive immunity for newborn
IgM Involved in early immune responses owing to involvement with IgD in activation of B-cell lymphocytes
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Figure 3-12 Internal view of the heart.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-13 Circulatory pathways.

(From Applegate EJ: The anatomy and physiology learning system, ed 3, Philadelphia, 2006, Saunders/Elsevier.)

Lymphatic System

Lymphatic system is composed of lymph, lymphatic organs, lymphatic vessels. Functions to return excess interstitial fluid to the blood, absorb fats and fat-soluble vitamins from digestive system, provide defense against invading microorganisms and disease. Lymph is interstitial fluid that has entered lymph vessels.

See Chapters 4, Head, Neck, and Dental Anatomy: nodes, tonsils; 6, General and Oral Pathology: lymphadenopathy.
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Figure 3-14 Lymph organs.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

CLINICAL STUDY

Age 23 YRS SCENARIO
Sex image Male image Female During an extraoral examination, a hard fi xed mass, approximately 6 mm wide by 36 mm long by 6 mm deep, is noted on the right side of the neck; enlargement is clearly visible but no discomfort is noted when it is palpated. Other enlarged areas have been detected by the patient in his armpit and groin areas on same side. He states that he feels fi ne, although he tires easily. Intraoral exam shows poor oral hygiene and moderate gingivitis but no evidence of caries, only decalcifi cation.
Height 6′2″
Weight 185 LBS
BP 112/69
Chief Complaint “There is a swelling on my neck that has been there for 6 months and is getting larger.”
Medical History Broken kneecap at age 8
Current Medications None
Social History

Respiratory System

Respiratory system includes the upper and lower respiratory tracts and the lungs (Figure 3-15). It functions to move gases to and from exchange surfaces, where diffusion can occur. Defends body against pathogens, permits speech, helps regulate acid-base balance in body.

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Figure 3-15 Respiratory tract.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Digestive System

Digestive system includes gastrointestinal (alimentary) tract (GIT; includes oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus) and accessory organs (liver, gallbladder, pancreas) (Figure 3-16). Embryologically and physiologically, the mouth is the beginning of GIT. Functions include ingestion, mechanical digestion, chemical digestion, secretion, mixing and propelling movements, absorption, elimination of waste products, immunological functions (e.g., secretory IgA).

See Chapter 4, Head, Neck, and Dental Anatomy: oral cavity structure.
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Figure 3-16 Organs of the digestive system.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

Urinary System

Urinary system consists of kidneys, ureters, urinary bladder, urethra (Figure 3-17). Functions to rid wastes, regulate fluid volume, maintain electrolyte concentrations, control blood pH, secrete renin and erythropoietin responsible for long-term maintenance of blood pressure.

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Figure 3-17 Components of the urinary system.

(From Fehrenbach MJ, ed: Dental anatomy coloring book, St. Louis, 2008, Saunders/Elsevier.)

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Figure 3-18 Structure of the nephron.

(From Applegate EJ: The anatomy and physiology learning system, ed 3, Philadelphia, 2006, Saunders/Elsevier).

Reproductive System

Reproductive system consists of the gonads (testes), ducts, accessory glands, penis in the male and gonads (ovaries), uterine tubes, uterus, vagina, external genitalia, mammary glands in the female.

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Figure 3-19 Organs of the female reproductive system.

(From Applegate EJ: The anatomy and physiology learning system, ed 3, Philadelphia, 2006, Saunders/Elsevier).

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Figure 3-20 Structures of the male reproductive system.

(From Applegate EJ: The anatomy and physiology learning system, ed 3, Philadelphia, 2006, Saunders/Elsevier).

BIOCHEMISTRY

Biochemistry is the study of living matter or organisms at a molecular level. Requires understanding of how molecules are structured, bonding to form MORE complex structures and thus affect living matter. Hydrocarbons are carbon- and hydrogen-based molecules that exist in several different forms and have various properties. Found within several products used daily (including in the dental office) and also form major components of the body.

Jan 1, 2015 | Posted by in Dental Hygiene | Comments Off on 3: Anatomy, Biochemistry, and Physiology
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