Organization of the

Human Body

Chapter 1 – Organization of the Human Body

What are the definitions of Anatomy and Physiology?

• Anatomy – The study of the shape and structure of an organism’s body and the placement of body parts.

• Physiology – The study of the functions of the body parts.

*Anatomists rely on observation while physiologists use experimentation.

Levels of Organization1. Subatomic particle- Neutron, proton, and electron2. Atom- The smallest unit of matter3. Molecule- Two or more atoms bonded together (H2O)4. Organelle- Parts of a cell with a specific job (mitochondria)5. Cell- The most basic unit of life6. Tissue- Groups of cells functioning together (Epithelial, nervous, muscle, and connective)7. Organ- Groups of tissues functioning together (stomach)8. Organ System- Groups of organs functioning together (digestive system)9. Organism- Groups of organ systems functioning together

Six Characteristics of Life

1. Responsiveness – Reacting to changes in the internal and external environment (Ex. Pupil dilation)

2. Reproduction – Cells come from the splitting and fusing of existing cells.

3. Growth – Increase in the size and/or number of and the maturation of these cells.

4. Genetic Material (Heredity) –DNA within a cell is passed on to offspring cells.

5. Metabolism – All chemical reactions carried out in organisms which allow for growth, repair, creation of energy and release of heat.

6. Homeostasis - The body maintaining a stable internal environment such as blood sugar levels, body temperature, and heart rate.

A great example of the power of genetics:

Examples of Homeostasis in the Human Body

How does Homeostasis happen?

• Maintained by feedback mechanisms (parts of the body communicating with one another).

• The 3 basic components of a feedback mechanism are a receptor, a control center and an effector.

• Example- When the heart rate increases, the blood pressure (pressure of blood on the walls of vessels) increases. Higher bp is detected by nerve cells in the walls of blood vessels called baroreceptors (receptor). These send a message to the brain (control center) which tells the heart (effector) to slow down.

Anatomical TerminologyAnatomical Position – stand erect, face observer, head level, eyes face forward, feet flat and directed forward,

and palms up

Anatomical Terms- Cephalic- Head- Facial- Face- Frontal- Forehead- Orbital- Eye- Otic- Ear- Nasal- Nose- Buccal- Cheek- Oral- Mouth- Mental- Chin- Cranial- Skull- Occipital- Back of head- Cervical- Neck- Pectoral- Chest- Sternal- Breastbone

- Umbilical- Belly button- Coxal- Hip- Pubic- Genital region- Scapular- Shoulder blade- Vertebral- Backbone- Acromial- Top of shoulder- Axillary- Armpit- Brachial- Arm above elbow- Antecubital- Front of elbow- Olecranal- Back of elbow- Antebrachial- Arm below elbow- Carpal- Wrist- Manual- Hand- Palmar- Palm

- Digital- Fingers and toes- Inguinal- Groin- Gluteal- Buttocks- Femoral- Thigh- Patellar- Knee cap- Popliteal- Back of knee- Crural- Front of lower leg- Sural- Back of lower leg- Fibular or peroneal- Side of lower leg- Tarsal- Ankle- Pedal- Foot- Calcaneal- Heel- Plantar- Sole of foot

- Dorsum- Top of foot/back of hand

Let’s Review

Directional Terms• Describe the position of one body part in

relation to another.

– Anterior or ventral- Closer to the front of the body

– Posterior or dorsal- Closer to the back of the body

– Caudal or inferior- Below

– Cephalic or superior – Above

– Medial- Closer to the midline of the body

– Lateral- Farther from the midline of the body

A few more directional terms…

– Proximal- Closer to the point of attachment of a limb and the trunk

– Distal- Farther from the point of attachment of a limb and a trunk

– Superficial or external- Closer to the surface of the body

– Deep or internal- Farther from the surface of the body

Directional Terms Practice

• The lips are __________ to the teeth.

• The wrist is ___________ to the elbow.

• The nose is ____________ to the eyes.

• The neck is ____________ to the head.

• The skin is ____________ to the muscles.

Body Sections Cuts made through the body in the direction of a certain plane.

• Sagittal – divides the body into right and left portions•midsagittal – equal right and left halves•parasagittal – unequal right and left halves

•Transverse – divides the body into superior (top) and inferior (bottom) portions

•Coronal or Frontal – divides the body into anterior and posterior sections

•Oblique- A cut made at an angle (not perpendicular or parallel).

Body Planes

Let’s Review

Body Cavities• Spaces that contain, protect, separate, and

support internal organs

– Dorsal cavity- contains the cranial cavity and the spinal cavity. The cranial cavity encloses the brain and the spinal cavity encloses the spinal cord.

– Ventral cavity- contains the thoracic cavity and the abdominopelvic cavity.• The diaphragm is a muscle that divides the

thoracic and abdominopelvic cavities.

Thoracic and Abdominopelvic Cavities• In the center of the thoracic cavity is the mediastinum which

contains the heart, thymus, esophagus, trachea and bronchi.• The heart is lined with pericardium

– the parietal pericardium lines the cavity while the visceral pericardium covers the heart. A thin layer of serous fluid separates the two layers.

• The lungs are lined with pleura– the parietal pleura lines the cavity while the visceral pleura

covers the lungs. A thin layer of serous fluid separates the two layers.

• The Abdominopelvic cavity can be divided into the abdominal cavity (contains the stomach, liver, gall bladder, pancreas, spleen, small intestine, appendix, kidneys and part of the large intestine) and the pelvic cavity (contains the bladder, reproductive organs, rectum and the remainder of the large intestine.

Thoracic Pleural and Pericardial Layers

Abdominopelvic cavity continued…• The peritoneum lines the abdominopelvic cavity; a

parietal peritoneum lines the wall while visceral peritoneum covers the organs.

• The abdominopelvic cavity is subdivided into nine regions:

Abdominopelvic Peritoneum

Organ Systems-a. Integumentary System – skin, nails, hair – covers

the body, senses changes outside the body, helps regulate body temperature

b. Skeletal System – bones, ligaments – supports, protects, provides a framework, stores minerals, houses blood forming tissues

c. Muscular System – muscles, tendons – provides body movement, posture, and body heat

d.Nervous System – brain, spinal cord, nerves, sensory organs – receives, processes and sends electrical impulses

e. Endocrine System – glands that secrete hormones – integrate metabolic functions

f. Cardiovascular System – heart, blood, blood vessels – distributes oxygen and nutrients throughout the body while removing wastesg. Lymphatic System – lymphatic vessels, lymph nodes, thymus, and spleen – drains excess tissue fluid and houses cells of immunityh. Digestive System – mouth, esophagus, stomach, intestines, pancreas, liver, gall bladder – receives, digests, and absorbs nutrientsi. Respiratory System – lungs, bronchi, bronchioles, alveoli– exchanges gases between the blood and airj. Urinary System – kidneys, ureters, bladder, urethra – removes wastes from the blood and helps maintain water and electrolyte balance

•Reproductive System – produces new organisms- Male Reproductive System – testes, glands, penis and vessels for sperm conduction- Female Reproductive System – ovaries, fallopian tubes, uterus, cervix, vagina, external genitalia

MORE TERMS TO KNOW:

Disorder – any derangement or abnormality of function (hypertension) – ex. High blood sugar

Disease – more specific term for an illness characterized by a recognizable set of signs and symptoms (coronary artery disease) ex. Diabetes

Signs – objective changes that a doctor can observe and measure – bleeding, swelling, vomiting, diarrhea, fever, rash, paralysis

Symptoms – subjective changes in body function according to the individual – headache, nausea, muscle aches, fatigue

Signs and Symptoms Practice Problem:

Mononucleosis – spread by direct contact with secretions such as saliva. It is caused by a virus (EBV) – Epstein-Barr Virus

People with mono often have pharyngitis (sore throat), adenopathy (enlarged lymph nodes in the neck), and fever. People will also often exhibit extreme fatigue, chills, headache, muscle aches, joint aches, nausea, vomiting, abdominal pain, jaundice, and decreased appetite with weight loss. Others may have splenomegaly (enlarged spleen) during the second week of the illness. Sometimes people will have a rash, however, this is uncommon.

What are the signs?

What are the symptoms?