Copyright ©2012 Delmar, Cengage Learning. All rights reserved. Chapter 23 Anatomic Descriptors and Fundamental Body Structure

Copyright ©2012 Delmar, Cengage Learning. All rights reserved.

Chapter 23

Anatomic Descriptors and Fundamental Body Structure


Anatomical Position

• A body is said to be in the anatomical position when the patient is standing erect, with the arms down at the sides, and the palms of the hands facing forward


Appropriate Terminology forAnatomical Directions

• To describe exact location when charting, the body is divided by imaginary lines

• One line divides the body into right and left


Terms

• Medial– Toward the midline

• Proximal– Nearest the point of attachment

• Distal– Farthest from the point of attachment

• Lateral– Away from the midline


Appropriate Terminology forAnatomical Directions

• Another line divides the body into upper and lower halves

• Finally, a line divides the body into front and back


Terms

• Anterior– Toward the front

• Frontal– Toward the front

• Ventral– Toward the front or belly side

• Superior– Above the transverse plane

• Cranial– Toward the head

• Inferior– Below the transverse

plane• Caudal

– Toward the tail or feet• Posterior

– Toward the back


Body Cavities and Major Organs

• The body is divided into two main cavities:1.Anterior or ventral

• Cavity toward the belly side that contains the head, chest, and major abdominal organs

2.Posterior or dorsal • Cavity toward the back that contains the brain and

spinal cord


Body Cavities


The Diaphragm

• Diaphragm– A large dome-shaped muscle that separates the

thoracic cavity from the abdominal cavity


The Organs of the Abdomen

• The abdomen contains the:– Stomach– Small intestine– Most of the large intestine– Liver– Spleen– Pancreas– Gallbladder

The Regions of the Abdomen

• Because of its size, the abdomen is first divided into four areas called quadrants.


The Regions of the Abdomen

• The abdomen is then divided into 9 regions for purposes of identification and reference.



The Basic Characteristics of a Cell

• The cell is the basic building block of the human body:– Cells need nutrients and oxygen to survive.– Cells perform specific functions.– Cells produce heat and energy.– Cells can give off waste products.– Some cells can reproduce themselves.



• Organelles are minute bodies within the cytoplasm:

– Nucleus– Mitochondria– Ribosomes– Centriole

• Some organelles physically separate the chemical reactions that are not compatible.

• Organelles also control the time when reactions take place.

Endoplasmic reticulum Golgi apparatus Lysosomes



• Chromosomes– Located within the nucleus, each human has 23

pairs of chromosomes that store the hereditary material passed from one generation to the next

– 22 pairs are identical.– The 23rd pair are the sex chromosomes:

• XY = male• XX = female



• Cytoplasm– Fluid that makes up the cell

• Cell membrane– Separates the cell from the surrounding

environment• Cytoplasm

– Semisolid fluid within the membrane where chemical reactions, such as respiration, occur


What Happens When Mutations Occur

• DNA that is lost, rearranged, or paired in error results in a change in the genetic code called a mutation.


Six Ways Molecules Pass Through Cell Membranes

1.Diffusion– Gas, solids, or liquids are distributed evenly

through a medium.

2.Osmosis– Diffusion of water or another solvent through a

selectively permeable membrane



3.Filtration– Movement of solutes and water across a

semipermeable membrane– Filtration occurs as a result of force such as gravity

or blood pressure.

4.Active transport– Molecules move across a membrane from an area

of low concentration to an area of high concentration.



5.Phagocytosis– White blood cells become phagocytes and engulf

bacteria, cell fragments, or damaged cells.

6.Pinocytosis– Cells engulf large molecules of liquid materials;

cell drinking


The Patterns of Inheritance andHow They Affect a Trait

• A trait is a recognizable result of the effect of a gene or a group of genes– 3 patterns of inheritance can produce these traits

1. Dominant genes: produce the trait2. Recessive genes: produce the trait if both parents

have the same mutation3. X-linked: traits that are sex linked


Genetic and Congenital Disorders

• These disorders can result from improper sex cell division at the time of fertilization, from the inheritance of altered genes, or as the result of environmental factors or poisons.


Cleft Lip and Cleft Palate

• Cleft lip– A structural defect is present in the upper lip

caused by failure of the soft or bony tissues to unite during the 8th to 12th week of gestation.

• Cleft palate– A structural defect is present in the roof of the

mouth caused by failure of the soft or bony tissues to unite during the 8th to 12th week of gestation.


Color Vision Deficiency

• Inaccurately called “colorblindness” – most people see some colors.

• The most common problem is an inability to distinguish between red and green.

• There is no treatment to correct the problem; people must learn to compensate.


Cystic Fibrosis

• Affects multiple systems; a generalized dysfunction of the exocrine glands.

• 30,000 people affected in the U.S.; median age of survival is 37 years.

• All states require infant screening to identify cystic fibrosis before leaving the hospital.


Down Syndrome

• A genetic syndrome caused by improper cell division• Occurs in about 1 in every 1,000 births, depending

on the mother’s age• The result is an extra chromosome 21.• Down syndrome has several physical characteristics,

e.g., slanting eyes, large tongue, pug nose, and a small head.

• Mental retardation occurs in all cases and there is some degree of growth restriction.


Dwarfism

• Condition that results in an abnormally undersized person.

• About 200 conditions that result in dwarfism; achondroplastic dwarfism accounts for 70% of cases.


Klinefelter’s Syndrome

• Sex-linked disorder where there is one or more extra X chromosomes; affects 1 in every 600 males.

• At puberty, the penis and testicles fail to mature and there is little body hair.

• Breasts may enlarge and long legs with a short, obese trunk are noted.


Spina Bifida

• A structural malformation of the spine• The posterior portion of the spinal tissues fails

to close during the first 3 months of pregnancy.


Talipes

• A structural deformity of one or both feet• Commonly called clubfoot• There may be varying degrees of inward,

outward, downward, or upward turning of one or both feet.


Turner’s Syndrome

• Sex-linked defect that affects about 1 in every 10,000 females.

• Only 45 chromosomes are present because the sex cells failed to divide correctly.

• Ovaries fail to develop.• The chest is wide and there is poor breast

development and underdevelopment of the genitalia.


Body System Interaction

• Because the body is so dependent on multiple systems to function, when diseases and disorders develop, often multiple systems are involved.


Discoveries in Genetics

• The Human Genome Project identified a 3 billion letter code of human DNA, which is the chemical sequence containing the basic information for building and running a human body.

• This sequence determines every human characteristic from eye color to vulnerability to disease.


Genetic Techniques

• Polymerase Chain Reaction• DNA Fingerprinting• Genetic Counseling• Gene Therapy• Genetic Engineering• Stem Cell Research


Cell to Tissue Progression

• When cells of the same type group together for a common purpose, they form a tissue.

• Tissue has four main classifications and is 60% to 99% water.


Four Main Types of Body Tissue

1.Epithelial tissue– Forms the body’s glands, covers the surface of the

body, and lines the body cavities

2.Connective tissue– Connects tissues together to form the organs and

body parts



3.Nerve tissue– The basic structural unit of this tissue is the

neuron, which serves as the body’s communication network.

– These neurons are made up of a nerve cell body and fibers that resemble tree branches to bring impulses toward the cell and carry impulses away from the cell.



– Sensory neurons in the skin or sensory organs send impulses to the brain and spinal cord.

– Interneurons carry impulses to another neuron.– Motor neurons receive an impulse and send a

message, which causes a reaction.



4.Muscle tissue– Designed to contract on stimulation– Involuntary action occurs without control or

conscious awareness, such as the heartbeat and respirations.

– Tissues controlled at will by brain impulses are called voluntary muscle tissue.


Body Organs

• The organs are made up of two or more types of tissues working together to perform a specific body function.


Body Systems

• The human body is made up of 10 body systems and the organs of each are discussed in the unit that relates to that particular body system.


The Body Systems


The 10 Body Systems

Integumentary– Skin

Muscular system– Muscles

Skeletal system– Bones and joints

Nervous system– Brain and spine

Endocrine system– 9 glands


The 10 Body Systems

Circulatory system – Heart and blood vessels

Respiratory system– Mouth, nose, and lungs

Digestive system– Intestines

Urinary system– Bladder, kidneys, ureters, and urethra

Reproductive– Sex organs

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Copyright ©2012 Delmar, Cengage Learning. All rights reserved. Chapter 23 Anatomic Descriptors and Fundamental Body Structure