Introduction to the Human Body

Anatomy- science of structure

- relationships revealed by dissection and imaging techniques

Anatomy and Physiology?

Physiology- science of body functions- includes the study of

homeostasis (keeping the organs

systems of the body in balance)

Levels of Organization

Systems of the Human Body• Integumentary System consists

of the skin and related structures

(hair, nails, and glands).– Protects body, regulates

temperature, and eliminates wastes through sweat and other secretions

• Skeletal System consists of the bones and joints.– Provides protection and support

– Houses cells that will become red blood cells, white blood cells, and

platelets

• Muscular System consists of skeletal muscles, as smooth muscle and cardiac muscle.– With the skeletal system facilitates

movement and maintains posture

– Generates heat necessary for warm-blooded organisms to

maintain a constant body temp.

Systems of the Human Body

• Nervous System consists of the brain, spinal cord, nerves, and sensory

organs).– Senses and responds to body

conditions through

nerve impulses

Systems of the Human Body• Endocrine System consists of

hormone- producing cells and glands scattered throughout the body.– Regulates the body through

chemical

mechanisms (by releasing hormones into the blood)

• Cardiovascular System consists of the heart, blood, and blood vessels.– Carries blood and nutrients to specific

locations

– Regulates body temperature, and water balance

Systems of the Human Body• Lymphatic and Immunity System

consists of the lymphatic fluid, nodes, and lymphocytes – and other associated organs of

the immune system - tonsils, spleen and thymus – Transports fats and proteins to the

cardiovascular system

– Filters blood and protects against disease

• Respiratory System consists of the upper airways, the trachea and major

bronchi, and the lungs.– Extracts O2 and eliminates CO2

– In conjunction with the kidneys, regulates acid/base balance

Systems of the Human Body• Digestive System consists of the esophagus,

stomach and intestines, and the accessory digestive glands like the salivary glands, liver, and gallbladder.– Accomplishes the physical and chemical

breakdown of food and elimination of waste

• Urinary System consists of the kidneys, ureters, bladder, and urethra.– Involved in the collection and

excretion of waste products in urine, and the

regulation of fluid, electrolyte, & acid/base balance

Systems of the Human Body• Reproductive System consists of the ovaries, uterus and vagina in

the female, and the testes and penis in the male (along with associated organs and glands in both sexes).– Reproduction of an individual or organism

Essential Life Processes• Metabolism

- Sum of all the chemical process that occur in the body

- Catabolism: the breakdown of complex chemical substances into simpler components

- Anabolism: the building up of complex chemical substances from smaller, simpler

components

• Responsiveness

- Body’s ability to detect and respond to changes

- Decrease in body temperature

- Responding to sound

- Nerve (electrical signals) and muscle cells (contracting)

Essential Life Processes• Movement

- Motion of the whole body

- Organs, cells, and tiny subcellular structures

- Leg muscles move the body from one place to another

• Growth - Increase in body size

- Due to an increase in existing cells, number of cells, or both

- In bone growth materials between cells increase

• Differentiation

- Development of a cell from an unspecialized to specialized state

- Cells have specialized structures/functions that differ from precursor cells

- Stem cells give rise to cells that undergo differentiation

• Reproduction

- Formation of new cells (growth, repair, or replacement)

- Production of a new individual

HomeostasisA condition of equilibrium in the body’s internal environment.

Maintaining the internal environment within physiological limits is extremely important.

Homeostasis is continually being disrupted by different stimuli:– external stimuli: intense heat, cold , and lack of oxygen– internal stimuli: psychological stresses, exercise

Disruptions are usually mild & temporary

If homeostasis is not maintained, death may result.

Animation: Communication, Regulation and Homeostasis

• Body fluid compartments– Intracellular fluid (ICF) - fluid within cells– Extracellular fluid (ECF) - fluid outside cells

- Interstitial fluid – ECF between cells and tissues

ICF

ECF

Homeostasis

• ECF Types and Locations

• Blood Plasma- ECF within blood vessels

• Lymph- ECF within lymphatic vessels

• Cerebrospinal fluid (CSF)- ECF in the brain and spinal cord

• Synovial fluid- ECF in joints

• Aqueous humor and vitreous body- ECF in eyes

Homeostasis

• Interstitial Fluid and Body Function

• Cellular function depends on the regulation of composition of interstitial fluid

• Composition of interstitial fluid changes as it moves– Movement back and forth across capillary walls

provide nutrients (glucose, oxygen, ions) to tissue cells and removes waste (carbon dioxide)

Homeostasis

Control of Homeostasis• Homeostasis is constantly being disrupted

– Physical insults• Intense heat or lack of oxygen

– Changes in the internal environment• Drop in blood glucose due to lack of food

– Physiological stress• Demands of work or school

– Disruptions• Mild and temporary (balance is quickly restored)

• Intense and Prolonged (poisoning or severe infections)

• Receptor

– monitors a controlled condition

• Control center

– determines next action

• Effector

– receives directions from the control center

– produces a response that changes the controlled condition

Control of HomeostasisFeedback Loops

Negative & Positive Feedback Loops• Negative feedback loop

– original stimulus reversed – most feedback systems in the body are negative– used for conditions that need frequent adjustment– body temperature, blood sugar levels, blood pressure

• Positive feedback loop

–original stimulus intensified

–seen during normal childbirth

Feedback Loop Examples

• Positive Feedback Control of Labor

• Negative Feedback Control of Blood Pressure

Homeostatic Imbalances

• Disorder: abnormality of function

• Disease: homeostatic imbalance with distinct -– Symptoms: changes in body function felt by the patient

such as nausea – Signs: changes in body function that can be observed

by the doctor such as rash or fever

• Diagnosis: skill of distinguishing one disease from another

• Epidemiology: how a disease is transmitted

• Pharmacology: how drugs used to treat disease

Basic Anatomical Terminology

• Anatomical position

• Regions of the body

• Directional terms

• Anatomical planes and sections

• Body Cavities

• Abdominopelvic regions and quadrants

Anatomical Position

• Standardized position from which to describe directional terms

– standing upright

– facing the observer, head level

– eyes facing forward

– feet flat on the floor

– arms at the sides

– palms turned forward

• Prone position = lying face down

• Supine position = lying face up

Regional Terms

Directional Terms

Directional Terms

Body Planes

Sagittal

midsagittal

parasagittal

Frontal/Coronal

Transverse/Horizontal

Oblique

Body Planes and Sections

Body Planes and Sections

Body Planes and Sections

Body Cavities

Body Cavities - Thoracic

• Encircled by ribs, sternum, vertebral column and muscle

• Divided into 2 pleural cavities by mediastinum

• Mediastinum contains all thoracic organs except lungs

Body Cavities - Thoracic

Abdominopelvic Cavity

• Inferior portion of ventral body cavity below diaphragm

• Encircled by abdominal wall, bones & muscles of pelvis

Serous Membranes

Membrane on the organ

is called visceral

Membrane on the wall

of the cavity is called

the parietal

Pleural & Pericardial Membranes

• Visceral pleura clings to surface of lungs --- Parietal pleura lines chest wall

• Visceral pericardium covers heart --- Parietal pericardium lines pericardial sac

Peritoneum

• Visceral peritoneum --- serous membrane that covers the abdominal viscera (organs)

• Parietal peritoneum - -- serous membrane that lines the abdominal wall

Abdominopelvic Quadrants and Region

Medical Imaging

• Allows visualization of structures without surgery

• Useful for confirmation of diagnosis

• Examples:

Radiography Ultrasound (US)

CT PET

MRI Radionuclide scanning

Endoscopy

Radiography

Radiography

Radiography

Radiography

Radiography

Radiography

Computed Tomography (CT Scan)

Magnetic Resonance Imaging (MRI)

Ultrasound (US)

Positron Emission Tomography (PET)

Radionuclide Scanning

Endoscopy