Chapter 1

The Human Body:An Orientation

Overview of Anatomy and Physiology

✤ Anatomy – the study of the structure of body parts and their relationships to one another✤ Gross or macroscopic

✤ Regional – all structures in one part of the body✤ Systemic – each system individually✤ Surface – study of internal structures as they relate to skin above

✤ Microscopic✤ Cytology - study of cells✤ Histology - study of tissues

✤ Developmental✤ Embryology - study of the body before birth

✤ Physiology – the study of the function of the body’s structural machinery

✤ Considers the operation of specific organ systems:

✤ Renal physiology – kidney function

✤ Neurophysiology – workings of the nervous system

✤ Cardiovascular physiology – operation of the heart and blood vessels

✤ Focuses on the functions of the body, often at the cellular or molecular level

Overview of Anatomy and Physiology

✤ Function always reflects structure and form fits function!

✤ What a structure can do depends on its specific form.

✤ A change in anatomy can have a significant effect on physiology.

✤ Ex: sickle cell anemia

Principle of Complementarity

Levels of Structural Organization

✤ Elements/Atoms – atoms combined to form molecules

✤ Molecular – made of several chemicals

✤ Cellular – cells are made of molecules

✤ Tissues – consists of similar types of cells

✤ Organs – made up of different types of tissues

✤ Organ systems – consists of different organs that work closely together

✤ Organism – made up of the organ systems

Levels of Structural Organization

✤ A malfunction at any level has serious consequences to levels built upon it.

✤ Example: cystic fibrosis

Figure 1.1

Levels of Structural Organization

Chemicals

Molecules

Cellular

TissuesText

Organs

Organ System

Organism

Chemical

Molecular

Cellular

Tissues

Organ

Organ System

Organism

Anatomical road map

Anatomical PositionBody erect

Feet slightly apart and parallelArms hanging at sides Palms facing forward

Thumbs point away from body

Why do thumbs have to point out?

Directional Terms (body structures in relation to another)

✤ Superior – toward head

✤ Inferior – away from head

✤ Anterior – toward the front

✤ Posterior – toward the back of the body

✤ Medial – toward the midline

✤ Lateral – away from the midline

✤ Intermediate – between a more medial and lateral structure

✤ Proximal – closer to the origin of a limb on the body

✤ Distal – further from the origin of a limb on the body

✤ Superficial – toward the surface

✤ Deep – away from the surface

Directional Terms

Practice using Directional Terms

1.The wrist is _____________ to the hand.

2.The sternum (breastbone) is ___________ to the spine.

3.The brain is ______________ to the spinal cord.

4.The kidneys are ___________ to the liver.

5.The nose is ______________ to the cheekbones.

6.The thumb is _____________ to the fingers.

ANSWERS

1.The wrist is ___PROXIMAL__________ to the hand.

2.The sternum (breastbone) is __ANTERIOR_________ to the spine.

3.The brain is ___SUPERIOR___________ to the spinal cord.

4.The kidneys are ___INFERIOR________ to the liver.

5.The nose is __MEDIAL__________ to the cheekbones.

6.The thumb is ____LATERAL_________ to the fingers.

More Practice using Directional Terms

1.The ___________ is posterior to the ______________.

2.The ___________ is intermediate between the ________________and the _____________.

3.The_______________ is superficial to the ___________________.

4.The _________________ is deep to the ________________.

5.The _________________ is distal to the _________________.

Regional Terms (visible landmarks on surface of body)

✤ Axial – head, neck, and trunk

✤ Appendicular – appendages or limbs

✤ LABEL REGIONAL ANATOMY ON DIAGRAM

Figure 1.7b

✤ Locate the following pulse points on your body:

✤ Radial pulse

✤ Brachial pulse

✤ Carotid pulse

✤ Femoral pulse

✤ Popliteal pulse

Body Planes and Sections

✤ Sagittal – divides the body into right and left parts

✤ Midsagittal – sagittal plane that lies on the midline

✤ Frontal or coronal – divides the body into anterior and posterior parts

✤ Transverse or horizontal (cross section) – divides the body into superior and inferior parts

✤ Oblique section – cuts made diagonally

Body Planes

Figure 1.8

Planes

✤ On what plane could your desk be cut to yield a usable seat? Explain your answer.

Body Cavities

✤ The body has two major cavities:

✤ Dorsal Cavity

✤ Divided into two parts

✤ Cranial – skull and brain

✤ Vertebral – runs down the vertebral column and encases spinal cord and vertebrae

✤ Ventral cavity

✤ Houses the internal organs (viscera), and is divided into two subdivisions: thoracic and abdominopelvic

Figure 1.9

Ventral Cavity

✤ The ventral cavity is further divided into two parts:

✤ Thoracic

✤ Divided into three parts:

✤ Pleural cavities – each houses a lung

✤ Mediastinum – contains the pericardial cavity, and surrounds the remaining thoracic organs

✤ Pericardial – encloses the heart

Ventral Cavity, Continued

✤ Abdominopelvic

✤ Separated from the superior thoracic cavity by the diaphragm

✤ Divided into two parts

✤ Abdominal cavity – contains the stomach, intestines, spleen, liver, and other organs

✤ Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum

Ventral Body Cavity Membranes

✤ Parietal serosa covers the body walls

✤ Visceral serosa covers the internal organs

✤ Serous fluid separates the serosae

Figure 1.10

Other Body Cavities

✤ Oral and digestive – mouth and cavities of the digestive organs

✤ Nasal –located within and posterior to the nose

✤ Orbital – house the eyes

✤ Middle ear – contain bones (ossicles) that transmit sound vibrations

✤ Synovial – joint cavities

Quiz Next Class on Safety and Positional and Directional Terms

Necessary Life Functions

1. Maintaining boundaries – internal environments never contact external environments

2. Movement – locomotion, propulsion (peristalsis), and contractility

3. Responsiveness – ability to sense changes in the environment and respond to them

4. Digestion – breakdown of ingested foodstuff

5. Metabolism – all the chemical reactions that occur in the body

6. Excretion – removal of wastes from the body

7. Reproduction – continuing a species; offspring

8. Growth – increase in size of a body part or of the organism

Necessary Life Functions

Survival Needs

1. Nutrients – chemical substances used for energy and cell building

2. Oxygen – needed for metabolic reactions

3. Water – provides the necessary environment for chemical reactions

4. Normal body temperature – provide safe environment for chemical reactions to take place

5. Atmospheric pressure – required for proper breathing and gas exchange in the lungs

Organ Systems of the Body

✤ Integumentary system

✤ Composed of the skin, sweat glands, oil glands, hair, and nails

✤ Forms the external body covering - protects deep tissue from injury

Organ Systems of the Body

✤ Skeletal system

✤ Composed of bone, cartilage, and ligaments

✤ Protects and supports body organs

✤ Provides the framework for muscles

✤ Site of blood cell formation

✤ Stores minerals

Organ Systems of the Body

✤ Muscular system

✤ Composed of muscles and tendons

✤ Allows for movement

✤ Maintains posture

✤ Produces heat

Organ Systems of the Body

✤ Nervous system

✤ Composed of the brain, spinal column, and nerves

✤ Is the fast-acting control system of the body

✤ Responds to stimuli by activating muscles and glands

Organ Systems of the Body

✤ Cardiovascular system

✤ Composed of the heart and blood vessels

✤ The heart pumps blood

✤ The blood vessels transport blood throughout the body

✤ Lymphatic system

✤ Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels

✤ Picks up fluid leaked from blood vessels and returns it to blood

✤ Disposes of debris in the lymphatic stream

✤ Houses white blood cells involved with immunity

Organ Systems of the Body

✤ Respiratory system

✤ Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs

✤ Keeps blood supplied with oxygen and removes carbon dioxide

Organ Systems of the Body

✤ Digestive system

✤ Composed of the oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver

✤ Breaks down food into absorbable units that enter the blood

✤ Eliminates indigestible foodstuffs as feces

Organ Systems of the Body

✤ Urinary system

✤ Composed of kidneys, ureters, urinary bladder, and urethra

✤ Eliminates nitrogenous wastes from the body

✤ Regulates water, electrolyte, and pH balance of the blood

Organ Systems of the Body

✤ Reproductive system

✤ Main function is the production of offspring

✤ Also produces sex hormones

✤ Males - testosterone

✤ Females - estrogen

Organ Systems of the Body

Organ System Interrelationships

✤ Each organ system depends upon another

✤ The integumentary system protects the body from the environment

✤ Digestive and respiratory systems take in nutrients and oxygen

Figure 1.3

Organ System Interrelationships

✤ Nutrients and oxygen are distributed by the blood

✤ Wastes are eliminated by the urinary and respiratory systems

Homeostasis

✤ Homeostasis

✤ The ability to maintain a relatively stable internal environment despite outside forces

✤ The internal environment of the body is in a dynamic state of equilibrium

✤ Many systems interact to maintain homeostasis

Homeostatic Control Mechanisms

✤ How is homeostasis controlled?

✤ Receptor monitors the environment for changes

✤ When change occurs, a control center sets the point at which the variable is maintained

✤ An effector responds to the stimulus

Figure 1.4

Homeostatic Control Mechanisms

Figure 1.5

Negative Feedback

✤ In negative feedback systems, the output shuts off the original stimulus

✤ Example: Regulation of blood glucose levels

Other Negative Feedback Examples

✤ heart rate

✤ blood pressure

✤ breathing rate

✤ blood levels of oxygen, carbon dioxide, nutrients, and minerals

✤ Most control mechanisms are negative feedback loops.

Figure 1.6

Positive Feedback

✤ In positive feedback systems, the output enhances or exaggerates the original stimulus

✤ Example: Regulation of blood clotting, contractions in childbirth, lactation