1. The Human Body: An Orientation Part A1

2. Overview of Anatomy and Physiology
Anatomy – the study of the structure of body parts and their relationships to one another
Gross or macroscopic
Microscopic
Developmental
Physiology – the study of the function of the body’s structural machinery

3. Gross Anatomy
Deals with the examination of relatively large structures and features usually visible to the naked eye
Types of Gross Anatomy
Surface anatomy – study of general form and superficial markings
Regional anatomy – anatomical organization of specific areas of the body
Systemic anatomy – study of the structure of organ systems
Developmental anatomy – deals with the changes in form that occur between conception and physical maturity
Clinical anatomy – deals with subspecialties important in clinical practice

4. Deals with structures that cannot be seen without magnification
Microscopic Anatomy
Deals with structures that cannot be seen without magnification
Two major subdivisions:
Cytology – study of the cell
Histology – study of tissues

5. Developmental Anatomy
Traces structural changes throughout life
Embryology – study of developmental changes of the body before birth

6. Physiology
Focuses on the functions of the body, often at the cellular or molecular level
Subdivided into several specialities:
Cell physiology – deals with events at the chemical and molecular levels within and between cells
Special physiology – physiology of specific organs
Systemic physiology – all aspects of the functioning of specific organ systems
Pathological physiology – study of the effects of diseases on organ or system functions

7. Principle of Complementarity
Function always reflects structure
What a structure can do depends on its specific form

8. Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level Cells are made up of molecules 2
Atoms 1
Chemical level Atoms combine to form molecules
Smooth muscle tissue
Heart 3
Tissue level Tissues consist of similar types of cells
Cardiovascular system
Blood vessels
Epithelial tissue
Smooth muscle tissue
Blood vessel (organ) 6
Organismal level The human organism is made up of many organ systems
Connective tissue 4
Organ level Organs are made up of different types of tissues 5
Organ system level Organ systems consist of different organs that work together closely
Figure 1.1

9. Organ Systems of the Body
Integumentary system
Forms the external body covering
Composed of the skin, sweat glands, oil glands, hair, and nails
Protects deep tissues from injury and synthesizes vitamin D

10. 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

11. Organ Systems of the Body
Muscular system
Composed of muscles and tendons
Allows manipulation of the environment, locomotion, and facial expression
Maintains posture
Produces heat

12. 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

13. 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

14. Organ Systems of 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

15. 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

16. 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

17. 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

18. Organ Systems of the Body
Male reproductive system
Composed of prostate gland, penis, testes, scrotum, and ductus deferens
Main function is the production of offspring
Testes produce sperm and male sex hormones
Ducts and glands deliver sperm to the female reproductive tract

19. Organ Systems of the Body
Female reproductive system
Composed of mammary glands, ovaries, uterine tubes, uterus, and vagina
Main function is the production of offspring
Ovaries produce eggs and female sex hormones
Remaining structures serve as sites for fertilization and development of the fetus
Mammary glands produce milk to nourish the newborn

20. Organ Systems of the Body
Endocrine System
Glands secrete hormones that regulate processes such as growth, reproduction and nutrient use (metabolism) by body cells.
Composed of the pituitary gland, pineal gland, thyroid, thymus, adrenal glands, pancreas

21. Organ Systems Interrelationships
The integumentary system protects the body from the external environment
Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen

22. Organ Systems Interrelationships
Nutrients and oxygen are distributed by the blood
Metabolic wastes are eliminated by the urinary and respiratory systems
Figure 1.2

23. Nutrients – chemical substances used for energy and cell building
Survival Needs
Nutrients – chemical substances used for energy and cell building
Oxygen – needed for metabolic reactions
Water – provides the necessary environment for chemical reactions
Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates
Atmospheric pressure – required for proper breathing and gas exchange in the lungs

24. Chemical, thermal, and neural factors interact to maintain homeostasis
Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world
The internal environment of the body is in a dynamic state of equilibrium
Chemical, thermal, and neural factors interact to maintain homeostasis

25. Two types of regulation:
Homeostasis
Two types of regulation:
Autoregulation (intrinsic) regulation
When a cell, tissue, organ, or organ system adjusts its activities automatically in response to some environmental change.
Ex) When oxygen levels are low cells release chemicals to dilate blood vessels which increase blood flow

26. Homeostasis
Extrinsic regulation
Results from activities of the nervous or endocrine system.
Ex) Your nervous system can increase heart rate when exercising to increase blood flow. It can also reduce blood flow to less active organs increasing oxygen supply to other areas of the body.

27. Homeostatic Control Mechanisms
The variable produces a change in the body
The three interdependent components of control mechanisms are:
Receptor – sensor that is sensitive to a stimulus
Control center – receives and processes the information from the receptor and sends out a command
Effector – cell or organ that responds to command

28. Homeostatic Control Mechanisms3
Input: Information sent along afferent pathway to
Control center 4
Output: Information sent along efferent pathway to
Effector
Receptor (sensor) 2
Change detected by receptor 5
Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis
Stimulus: Produces change in variable 1
Imbalance
Variable (in homeostasis)
Imbalance
Figure 1.4

29. Example: Regulation of blood glucose levels
Negative Feedback
In negative feedback systems, the output shuts off the original stimulus
Example: Regulation of blood glucose levels

30. Negative Feedback
Figure 1.5

31. Example: Regulation of blood clotting
Positive Feedback
In positive feedback systems, the output enhances or exaggerates the original stimulus
Example: Regulation of blood clotting
Figure 1.6