1. The Human Body: An Orientation: Part A1
The Human Body: An Orientation: Part A

2. Overview of Anatomy and Physiology
Anatomy: The study of structure
Subdivisions:
Gross or macroscopic (e.g., regional, surface, and systemic anatomy)
Microscopic (e.g., cytology and histology)
Developmental (e.g., embryology)

3. Overview of Anatomy and Physiology
Essential tools for the study of anatomy:
Mastery of anatomical terminology
Observation
Manipulation
Palpation
Auscultation

4. Overview of Anatomy and Physiology
Physiology: The study of function at many levels
Subdivisions are based on organ systems (e.g., renal or cardiovascular physiology)

5. Overview of Anatomy and Physiology
Essential tools for the study of physiology:
Ability to focus at many levels (from systemic to cellular and molecular)
Basic physical principles (e.g., electrical currents, pressure, and movement)
Basic chemical principles

6. Principle of Complementarity
Anatomy and physiology are inseparable.
Function always reflects structure
What a structure can do depends on its specific form

7. Levels of Structural Organization
Chemical: atoms and molecules (Chapter 2)
Cellular: cells and their organelles (Chapter 3)
Tissue: groups of similar cells (Chapter 4)
Organ: contains two or more types of tissues
Organ system: organs that work closely together
Organismal: all organ systems

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

9. Chemical level Atoms combine to form molecules.1
Chemical level Atoms combine to form molecules.
Figure 1.1, step 1

10. Cellular level Cells are made up of molecules. 1
Organelle
Atoms
Molecule
Smooth muscle cell 2
Cellular level Cells are made up of molecules. 1
Chemical level Atoms combine to form molecules.
Figure 1.1, step 2

11. Cellular level Cells are made up of molecules.
Organelle
Atoms
Molecule
Smooth muscle cell 2
Cellular level Cells are made up of molecules.
Chemical level Atoms combine to form molecules. 1
Smooth muscle tissue 3
Tissue level Tissues consist of similar types of cells.
Figure 1.1, step 3

12. Cellular level Cells are made up of molecules.
Organelle
Atoms
Molecule
Smooth muscle cell 2
Cellular level Cells are made up of molecules.
Chemical level Atoms combine to form molecules. 1
Smooth muscle tissue
Tissue level Tissues consist of similar types of cells. 3
Blood vessel (organ)
Smooth muscle tissue
Connective tissue
Epithelial tissue 4
Organ level Organs are made up of different types of tissues.
Figure 1.1, step 4

13. Cellular level Cells are made up of molecules. 2
Organelle
Atoms
Molecule
Smooth muscle cell
Cellular level Cells are made up of molecules. 2
Chemical level Atoms combine to form molecules. 1
Smooth muscle tissue
Cardiovascular system 3
Tissue level Tissues consist of similar types of cells.
Heart
Blood vessels
Blood vessel (organ)
Smooth muscle tissue
Connective tissue
Epithelial tissue 4
Organ level Organs are made up of different types of tissues.
Organ system level Organ systems consist of different organs that work together closely. 5
Figure 1.1, step 5

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

15. Overview of Organ Systems
Note major organs and functions of the 11 organ systems (Fig. 1.3)

16. (a) Integumentary System Forms the external body covering, and
Hair
Skin
Nails
(a) Integumentary System
Forms the external body covering, and
protects deeper tissues from injury.
Synthesizes vitamin D, and houses
cutaneous (pain, pressure, etc.)
receptors and sweat and oil glands.
Figure 1.3a

17. Protects and supports body organs,
Bones
Joint
(b) Skeletal System
Protects and supports body organs,
and provides a framework the muscles
use to cause movement. Blood cells
are formed within bones. Bones store
minerals.
Figure 1.3b

18. Allows manipulation of the environment,
Skeletal
muscles
(c) Muscular System
Allows manipulation of the environment,
locomotion, and facial expression. Main-
tains posture, and produces heat.
Figure 1.3c

19. As the fast-acting control system of
Brain
Nerves
Spinal
cord
(d) Nervous System
As the fast-acting control system of
the body, it responds to internal and
external changes by activating
appropriate muscles and glands.
Figure 1.3d

20. Glands secrete hormones that regulate
Pineal gland
Pituitary
gland
Thyroid
gland
Thymus
Adrenal
gland
Pancreas
Testis
Ovary
(e) Endocrine System
Glands secrete hormones that regulate
processes such as growth, reproduction,
and nutrient use (metabolism) by body
cells.
Figure 1.3e

21. (f) Cardiovascular System
Heart
Blood
vessels
(f) Cardiovascular System
Blood vessels transport blood,
which carries oxygen, carbon
dioxide, nutrients, wastes, etc.
The heart pumps blood.
Figure 1.3f

22. (g) Lymphatic System/Immunity Picks up fluid leaked from blood vessels
Red bone
marrow
Thymus
Lymphatic
vessels
Thoracic
duct
Spleen
Lymph
nodes
(g) Lymphatic System/Immunity
Picks up fluid leaked from blood vessels
and returns it to blood. Disposes of debris
in the lymphatic stream. Houses white
blood cells (lymphocytes) involved in
immunity. The immune response mounts
the attack against foreign substances
within the body.
Figure 1.3g

23. (h) Respiratory System Keeps blood constantly supplied with
Nasal
cavity
Pharynx
Bronchus
Larynx
Trachea
Lung
(h) Respiratory System
Keeps blood constantly supplied with
oxygen and removes carbon dioxide.
The gaseous exchanges occur through
the walls of the air sacs of the lungs.
Figure 1.3h

24. Breaks down food into absorbable units that enter the blood for
Oral cavity
Esophagus
Liver
Stomach
Small
intestine
Large
intestine
Rectum
Anus
(i) Digestive System
Breaks down food into absorbable
units that enter the blood for
distribution to body cells. Indigestible
foodstuffs are eliminated as feces.
Figure 1.3i

25. Eliminates nitrogenous wastes from the
Kidney
Ureter
Urinary
bladder
Urethra
(j) Urinary System
Eliminates nitrogenous wastes from the
body. Regulates water, electrolyte and
acid-base balance of the blood.
Figure 1.3j

26. (k) Male Reproductive System (l) Female Reproductive System
Mammary
glands (in
breasts)
Prostate
gland
Ovary
Penis
Testis
Ductus
deferens
Scrotum
Uterine
tube
Uterus
Vagina
(k) Male Reproductive System
(l) Female Reproductive System
Overall function is production of offspring. Testes produce sperm and male sex
hormone, and male ducts and glands aid in delivery of sperm to the female
reproductive tract. Ovaries produce eggs and female sex hormones. The remaining
female structures serve as sites for fertilization and development of the fetus.
Mammary glands of female breasts produce milk to nourish the newborn.
Figure 1.3k-l

27. Organ Systems Interrelationships
All cells depend on organ systems to meet their survival needs
Organ systems work cooperatively to perform necessary life functions

28. Figure 1.2 Digestive system Takes in nutrients, breaks them
down, and eliminates unabsorbed
matter (feces)
Respiratory system
Takes in oxygen and
eliminates carbon dioxide
Food O2
CO2
Cardiovascular system
Via the blood, distributes oxygen
and nutrients to all body cells and
delivers wastes and carbon
dioxide to disposal organs
Blood
CO2 O2
Urinary
system
Eliminates
nitrogenous
wastes and
excess ions
Heart
Nutrients
Interstitial fluid
Nutrients and wastes pass
between blood and cells
via the interstitial fluid
Integumentary system
Protects the body as a whole
from the external environment
Feces
Urine
Figure 1.2

29. Necessary Life Functions
Maintaining boundaries between internal and external environments
Plasma membranes
Skin
Movement (contractility)
Of body parts (skeletal muscle)
Of substances (cardiac and smooth muscle)

30. Necessary Life Functions
Responsiveness: The ability to sense and respond to stimuli
Withdrawal reflex
Control of breathing rate
Digestion
Breakdown of ingested foodstuffs
Absorption of simple molecules into blood

31. Necessary Life Functions
Metabolism: All chemical reactions that occur in body cells
Catabolism and anabolism
Excretion: The removal of wastes from metabolism and digestion
Urea, carbon dioxide, feces

32. Necessary Life Functions
Reproduction
Cellular division for growth or repair
Production of offspring
Growth: Increase in size of a body part or of organism

33. Survival Needs Nutrients Oxygen Chemicals for energy and cell building
Carbohydrates, fats, proteins, minerals, vitamins
Oxygen
Essential for energy release (ATP production)

34. Normal body temperature
Survival Needs
Water
Most abundant chemical in the body
Site of chemical reactions
Normal body temperature
Affects rate of chemical reactions
Appropriate atmospheric pressure
For adequate breathing and gas exchange in the lungs

35. Homeostasis
Maintenance of a relatively stable internal environment despite continuous outside changes
A dynamic state of equilibrium

36. Homeostatic Control Mechanisms
Involve continuous monitoring and regulation of many factors (variables)
Nervous and endocrine systems accomplish the communication via nerve impulses and hormones

37. Components of a Control Mechanism
Receptor (sensor)
Monitors the environment
Responds to stimuli (changes in controlled variables)
Control center
Determines the set point at which the variable is maintained
Receives input from receptor
Determines appropriate response

38. Components of a Control Mechanism
Effector
Receives output from control center
Provides the means to respond
Response acts to reduce or enhance the stimulus (feedback)

39. Output: Information sent along efferent pathway to effector. 4 3
Input: Information sent along afferent pathway to control center.
Control Center
Afferent pathway
Efferent pathway 2
Receptor
Effector 5
Receptor detects change.
Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level. 1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4

40. Stimulus produces change in variable. BALANCE1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4, step 1

41. Receptor detects change.2
Receptor
Receptor detects change. 1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4, step 2

42. Input: Information sent along afferent pathway to control center. 3
Control Center
Afferent pathway 2
Receptor
Receptor detects change. 1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4, step 3

43. Output: Information sent along efferent pathway to effector. 4 3
Input: Information sent along afferent pathway to control center.
Control Center
Afferent pathway
Efferent pathway 2
Receptor
Effector
Receptor detects change. 1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4, step 4

44. Output: Information sent along efferent pathway to effector. 4 3
Input: Information sent along afferent pathway to control center.
Control Center
Afferent pathway
Efferent pathway 2
Receptor
Effector 5
Receptor detects change.
Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level. 1
IMBALANCE
Stimulus produces change in variable.
BALANCE
IMBALANCE
Figure 1.4, step 5

45. The response reduces or shuts off the original stimulus
Negative Feedback
The response reduces or shuts off the original stimulus
Examples:
Regulation of body temperature (a nervous mechanism)
Regulation of blood volume by ADH (an endocrine mechanism)

46. Temperature-sensitive Temperature-sensitive
Control Center
(thermoregulatory
center in brain)
Information sent
along the afferent
pathway to control
center
Information sent
along the efferent
pathway to
effectors
Afferent
pathway
Efferent
pathway
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Sweat glands
Sweat glands activated
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Stimulus
Body temperature
rises
BALANCE
Stimulus
Body temperature falls
Response
Body temperature rises;
stimulus ends
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Skeletal muscles
Efferent
pathway
Afferent
pathway
Shivering
begins
Information sent
along the efferent
pathway to effectors
Information sent
along the afferent
pathway to control
center
Control Center
(thermoregulatory
center in brain)
Figure 1.5

47. Negative Feedback: Regulation of Blood Volume by ADH
Receptors sense decreased blood volume
Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH)
ADH causes the kidneys (effectors) to return more water to the blood

48. The response enhances or exaggerates the original stimulus
Positive Feedback
The response enhances or exaggerates the original stimulus
May exhibit a cascade or amplifying effect
Usually controls infrequent events e.g.:
Enhancement of labor contractions by oxytocin (Chapter 28)
Platelet plug formation and blood clotting

49. 1 3 2 4 Break or tear occurs in blood vessel wall.
Positive feedback cycle is initiated. 3
Released chemicals attract more platelets.
Platelets adhere to site and release chemicals. 2
Positive feedback loop
Feedback cycle ends when plug is formed. 4
Platelet plug forms.
Figure 1.6

50. 1 Break or tear occurs in blood vessel wall.
Positive feedback cycle is initiated.
Figure 1.6, step 1

51. 1 2 Break or tear occurs in blood vessel wall.
Positive feedback cycle is initiated. 2
Platelets adhere to site and release chemicals.
Figure 1.6, step 2

52. 1 3 2 Break or tear occurs in blood vessel wall.
Positive feedback cycle is initiated. 3
Released chemicals attract more platelets.
Platelets adhere to site and release chemicals. 2
Positive feedback loop
Figure 1.6, step 3

53. 1 3 2 4 Break or tear occurs in blood vessel wall.
Positive feedback cycle is initiated. 3
Released chemicals attract more platelets.
Platelets adhere to site and release chemicals. 2
Positive feedback loop
Feedback cycle ends when plug is formed. 4
Platelet plug forms.
Figure 1.6, step 4

54. Homeostatic Imbalance
Disturbance of homeostasis
Increases risk of disease
Contributes to changes associated with aging
May allow destructive positive feedback mechanisms to take over (e.g., heart failure)