Introduction to Anatomy

1. Introduction to Anatomy Diane A. Young Brewbaker Technology Magnet High School

2. Anatomy • Anatomy – study of the structures of the body • Physiology – study of the functions of these structures

3. Body Planes VERTICAL PLANES: Vertical – up-and-down line at the right angle to the horizon Midsagittal 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.

6. Body Planes • Horizontal Planes: • Transverse plane (horizontal) – divides the body into superior (upper) and inferior (lower) portions • A transverse plane can be at the waist or any other level of the body

7. 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

8. 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 midline • Bilateral – relating to, or having, two sides

10. 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.

11. 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

12. Major Body Cavities • Dorsal Cavity divided into two parts, protects the structures of the nervous system that coordinate the bodily function • Cranial cavity – located within the skull, protects the brain • Spinal cavity – located within the spinal column, protects the spinal cord

13. 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.

15. 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)

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

19. 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.

20. Peritoneum, cont’d • Peritonitis– inflammation of the peritoneum. • Ascites – an abnormal accumulation of clear or milky serous (watery) fluid in the peritoneal cavity.

21. 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.

22. 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.

23. 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

24. 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.

25. 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.

26. 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.