1. Basic Anatomy, Homeostasis and Disease Human Anatomy-Unit I-Part A

2. How the Human Body is Studied
General
Anatomy is the study of body structure
Physiology is the study of how the body functions
These terms are almost always taken together
Directions in the body
A universal system has been designed to designate position and direction in the body
All terms assume the body is in an anatomical position, meaning:
Standing upright
Face front
Arms at sides with palms forward
Feet Parallel

3. How the Human Body is Studied
Directional Terms
Superior-above in the transverse plane
Inferior-below in the transverse plane
The heart is superior to the intestine, but inferior to the brain
Ventral-location towards the belly (anterior plane)
Dorsal-towards the back (anterior plane)
The stomach is ventral to the kidneys, the kidneys are dorsal to the stomach
Anterior-towards the frontside of (frontal plane)
Posterior-towards the backside of (frontal plane)
The nose is anterior to the ear.

4. How the Human Body is Studied
Cranial-near the head
Caudal-nearer the tail
The heart is cranial to the stomach, but caudal to the forehead.
Medial-towards the midline (saggital plane)
Lateral-away from the midline (saggital plane)
The heart is medial, the kidneys lateral
Proximal-near the trunk
Distal-farther from the trunk
The part of your thumb that joins your hand is proximal, the tip of the thumb is distal.

5. How the Human Body is Studied
Planes of Division
Used to visualize internal structures. The planes are:
Frontal (coronal)-a cut made giving you an anterior (ventral) and a posterior (dorsal) view.
Sagittal-a cut giving you left and right sections
Transverse-a horizontal cut that leaves you a superior and inferior part

6. How the Human Body is Studied
Planes of Division
Many diagnoses require tissue specimens to be looked at. Tissue may be cut in three ways:
Cross sectional-to give you round slices
Longitudinal-to give long slices
Oblique-an angled, cross sectional cut
Internally the body is also divided into cavities which contain the various organs. They include:
Dorsal-contains the cranial (brain) cavity, and the spinal cavity
Ventral-contains the thoracic, abdominal, and pelvic cavities

7. Homeostasis General Homeostasis
All chemical reactions that living things undergo make up their metabolism
Those reactions which involve breakdown are called catabolic
Those that build up are anabolic
Homeostasis
Living things attempt to maintain a steady state with both their internal and external environment
This steady state is known as homeostasis (literally “staying the same”)
Homeostasis is maintained by feedback

8. Homeostasis How feedback works
Feedback is a control system based on information returning to a source
When feedback fails, the body is said to be in a homeostatic imbalance
Moderate imbalance causes illness and disease
Severe imbalance will cause death
How feedback works
Most feedback systems work by keeping body conditions within a set normal range by reversing any upward or downward shift
In negative feedback, the body will attempt to reverse negative or positive changes

9. Homeostasis The body may also use positive feedback to regulate itself
In positive feedback, a given action promotes more of the same
An example involves childbirth, uterine contractions, and oxytocin
The nervous and endocrine systems are mostly involved in feedback and the maintenance of homeostasis. They coordinate with other body systems as well.

10. Disease
Definition-a homeostatic imbalance, involving an abnormality of the structure or function of a part, organ, or system
Categories of disease:
Infection-caused by infectious organisms (called pathogens) such as bacteria and viruses
Degenerative-involve degeneration (breaking down) of tissues in an organ system
Nutritional-may be due to a lack of essential substances, as well as the excessive intake of substances
Metabolic-any disruption to anabolic or catabolic reactions.

11. Disease Causes of disease Immune-any problem with the immune system
Neoplasm-any disease involving growth or tumors
Psychiatric disorders-mental disorders
Causes of disease
Outside factors that enter into the production of a disease are called predisposing factors
Predisposing factors to disease include age, gender, heredity, living conditions, emotional disturbance, physical and chemical damage, and preexisting illnesses

12. Diseases Studying Disease
Etiology is the study of the cause of any disease
Diseases are classified based on their severity and duration as follows:
Acute- severe but short lasting
Chronic- less severe but last longer
Subacute-intermediate, between the two
Communicable diseases can be transmitted between people, this can lead to an epidemic
Epidemics can stay in a particular region (endemic) or prevalent through the whole world (pandemic)

13. Diseases Treatment and Prevention
Before treatment can begin, a doctor must first decide exactly what is wrong. This is termed diagnosis
Before diagnosis, the doctor first must know what is wrong (symptoms) as well as predisposing conditions (history)
Once a diagnosis is made, the doctor will tell the patient what will happen. This is called the prognosis. The course of treatment for disease is known as therapy
In recent years, doctors and health care workers have been working towards stopping disease before it happens. This is known as prevention.

14. Diseases Areas for prevention include: Quitting smoking
Reducing alcohol intake
Improved diet
Weight control
exercise