Introduction to Anatomy

Introduction to Anatomy

Diane A. YoungBrewbaker Technology Magnet High School

Anatomy

Anatomy – study of the structures of the body

Physiology – study of the functions of these structures

Body PlanesVERTICAL PLANES:

Vertical – up-and-down line at the right angle to the horizonMidsagittal plane (midline) – the vertical plane that divides the body, from top to bottom into equal left and right halves.Sagittal plane – any vertical plane parallel to the midline that divides the body into unequal left and right portions.Coronal plan (frontal) – any vertical plane, at right angles to the sagittal plane that divides the body into anterior (front) and posterior (back) portions.

Body Planes

Horizontal Planes:Transverse plane (horizontal) –

divides the body into superior (upper) and inferior (lower) portionsA transverse plane can be at the waist or any other level of the body

Body Directions Body directions – relative location of the whole body or

an organ is described through the use of pairs of contrasting body direction terms. Ventral – the front or belly side of the body or organ Anterior – situated in the front. Also, the forward

part of an organ. Superior – uppermost, above or toward the head Cephalic – toward the head Proximal – situated nearest the midline or beginning

of a body structure Medial – direction toward or nearer the midline

Body Directions, cont’d Dorsal – to the back of the body or organ Posterior – situated in the back or on the back

part of an organ. Inferior – lowermost, below, or toward the feet Caudal – toward the lower part of the body Distal – situated farthest from the midline or

beginning of body structure Lateral – the direction toward or nearer the side

and away from the midlineBilateral – relating to, or having, two sides

Examples Anterior:

The mouth is anterior to the oral cavity. The trachea (windpipe) is anterior to the cervical

spine (vertebrae). The skin of the palm is anterior to the wrist bones

(carpals). The patella is anterior to the knee joint.

Posterior: The oral cavity is posterior to the mouth. The cervical vertebrae is posterior to the trachea.

Examples cont’d Superior:

The forehead is superior to the nose.The head is superior to the neck.The most superior portion of the femur is the

femoral head.The humerus is superior to the elbow joint.The heart is superior to the diaphragm

Inferior:The nose is inferior to the forehead.The neck is inferior to the head

Major Body Cavities

Dorsal Cavity divided into two parts, protects the structures of the nervous system that coordinate the bodily functionCranial cavity – located within the skull,

protects the brainSpinal cavity – located within the spinal

column, protects the spinal cord

Major Body Cavities Ventral Cavity divided into three parts, contains many of

the body organs that maintain homeostasis. Homeostasis means maintaining a constant internal environment. Thoracic cavity (chest cavity) – protects the heart

and lungs. The diaphragm is a muscle that separates the thoracic and abdominal cavities.

Abdominal cavity – contains primarily the major organs of digestion. Referred to as the abdomen.

Pelvic cavity – the space formed by the pelvic (hip) bones. It contains primarily the organs of the reproductive and excretory systems.

There is no division between the abdominal and pelvic cavities. Together they may be referred to as the abdominopelvic cavity.

Division of the Abdomen

To make it easier to describe where an organ or a pain is located, the abdomen is divided into four imaginary quadrants. Right upper quadrant (RUQ) Left upper quadrant (LUG) Right lower quadrant (RLQ) Left Lower quadrant (LLQ)

Regions of the Thorax and Abdomen Right and left hypochondriac regions.

Hypochondriac means below the ribs. This term also means the individual with an abnormal and excessive concern about his/her health.

Epigastric Region – epigastric means above the stomach

Right and left lumbar region. Lumbar refers to the inward curve of the spine

Umbilical region - The term umbilical means referring to the umbilicus (belly button or naval).

Right and left iliac regions - Iliac refers to the hipbone.

Hypogastric region - Hypogastric means below the stomach. The entire lower region of the abdomen is also referred to as the groin or inguinal area.

Peritoneum Peritoneum is the membrane that protects and

supports (suspends in place) the organs located in the abdominal cavity.

Parietal peritoneum – the outer layer of this membrane that lines the abdominal cavity

Visceral peritoneum – the inner layer of this membrane that surrounds the organs of the abdominal cavity. Visceral means relating to the internal organs (those enclosed within a cavity) especially the abdominal organs.

Mesentery – a layer of the peritoneum that suspends parts of the intestine within the abdominal cavity.

Retroperitoneal – means located behind the peritoneum of the abdominal cavity.

Peritoneum, cont’d

Peritonitis – inflammation of the peritoneum. Ascites – an abnormal accumulation of clear or

milky serous (watery) fluid in the peritoneal cavity.

Cytology Cytology is the study of the formation, structure,

and function of the cells. Cell membrane – the structure that surrounds and

protects the cell. A membrane is a thin layer of tissue that covers a surface, lines a cavity or divides a space or organ.

Cytoplasm is the material within the cell membrane that is not part of the nucleus.

Nucleus – is surrounded by the nuclear membrane. It is a structure within the cell that has two important functions: Controlling the activities and helps the cell divide.

Cells are the basic structural units of the body that are specialized and grouped together to form the tissues and organs.

Tissue The four main types of tissue are epithelial,

connective, muscle and nerve Epithelial tissue – form a protective covering

for all of the internal and external surfaces of the body.Epithelium – the specialized epithelial tissue

that forms the epidermis of the skin and the surface layer of mucous membranes.

Endothelium – specialized epithelial tissue that lines the blood and lymph vessels, body cavities, glands and organs

Glands are made up of specialized epithelial tissues that are capable of producing secretions.

Tissue Connective tissues support and connect organs and

other body tissues Adipose tissue, also known and fat, provides

protective padding, insulation, support and acts as a nutrient reserve.

Loose connective tissue – surrounds various organs and supports both nerve cells and blood vessels.

Blood and lymph are liquid connective tissue Bone and cartilage are dense connective tissue

We will discuss blood, lymph, bone and cartilage later

Tissue Muscle tissue – contains cell material with the

specialized ability to contract and relax Nerve Tissue – contains cells with the specialized

ability to react to stimuli and conduct electrical impulses.

Glands A gland is a group of specialized epithelial cells that

form secretions. A secretion is the substance produced by a gland. Exocrine glands, such as sweat glands, secrete

their chemical substances into ducts that lead either to other organs or out of the body.

Endocrine glands, which secrete hormones, do not have ducts. These secretions flow directly into the bloodstream for transportation to organs and other structures throughout the body.

Organs

An organ is somewhat independent part of the body that performs a special function or functions.

The tissues and organs of the body are organized into systems that perform specialized functions.