1. The Human Body
An Overview

2. Anatomy From Latin tomy (to cut) and ana (apart)
It’s the study of structure and shape of the body and its parts
Two types:
Gross anatomy: large structures, easily observable
Microscopic anatomy: small structures only visible with microscope

3. Gross Anatomy

4. Microscopic anatomy

5. Levels of Structural Organization

6. Structural complexity
Six levels of complexity
Chemical level
Atoms: smallest building blocks of matter
Molecules: combinations of atoms to make water, sugars, and proteins
Atoms combine to form molecules
Nitrogen

7. Cellular level
Molecules combine to form cells, which vary in size and shape, reflecting different functions of body

8. Similar types of cells group to form tissues
Tissue level
Similar types of cells group to form tissues
Four basic tissue types:
Epithelial tissue (skin, membranes)
Connective tissue (tendons, cartilage, ligaments and bone)
Muscular tissue (muscles)
Neural tissue (spinal cord, brain matter)

9. Organ level
Tissue or multiple tissues that form a structure that performs a specific function
Ex: small intestine is made out of all four tissue types

10. Group of organs that cooperate to accomplish a common purpose
Organ system level
Group of organs that cooperate to accomplish a common purpose
Ex: digestive system includes esophagus, stomach, small and large intestines, and more
Total of 11 organ systems
How they work = physiology!

11. Organismal level
Highest level of organization
Human organisms have similar organ systems and chimpanzees, but very different organ systems than mosquitoes

12. Physiology
Studies functions (how it works) of human body and its parts
Anatomists observe structures while physiologists employ experimentation

13. Organ systems Integumentary system
External covering of the body (skin)
Protects deeper tissue from injury or infection
Synthesizes vitamin D
excretes salts and urea in perspiration
helps regulate body temperature
contains pain, temperature, and pressure receptors for environmental cues

14. Muscular system
Muscles of body
Contract or shorten to move skeleton
Maintains posture
Produces heat

15. Skeletal system
All bones, cartilages, ligaments and joints make up skeletal system
Protects and supports body organs
Provides muscle attachment for movement
Forms blood cells (hematopoiesis) in bone marrow
Provides and stores minerals

16. Nervous system Brain, spinal cord, nerves, and sensory receptors
Speedy control system that responds to external stimuli
Light
Sound
Temperature changes
Pain
Pressure
Central nervous system (brain and spinal cord) assesses information and responds by activating appropriate effector (muscles or glands)

17. Endocrine system
A series of glands that slowly control body by producing and releasing hormones for growth, metabolism, and reproduction
Pituitary gland
Thyroid gland
Parathyroid glands
Adrenal glands
Thymus
Pancreas
Pineal gland
Ovaries (females)
Testes (males)

18. Cardiovascular system
Heart and blood vessels
Work together to transport materials in blood
Nutrients
Hormones
Oxygen
Carbon dioxide
Waste

19. Lymphatic system Lymphatic vessels, lymph nodes, spleen, and tonsils
Returns fluid leaked from blood back to blood vessels
Lymph nodes (and others) help cleanse blood and store cells involved in immunity

20. Respiratory system
Lungs, nasal passages, pharynx, larynx, trachea, and bronchi
Supplies oxygen
Removes carbon dioxide

21. Digestive system
Mouth, esophagus, stomach, small and large intestines, liver, pancreas, and rectum
Breaks down food
Deliver products to blood for dispersal to body
Undigested food leaves body through anus as feces
Reclaim water for bodily use

22. Urinary(excretory) system
Kidneys, ureters, bladder, urethra
Rids body of waste products
Nitrogen-containing urea and uric acid from breakdown of proteins and nucleic acids
Maintains body’s water and salt/electrolyte balance
Regulates acid-base balance of blood

23. Reproductive system
Males: scrotum, penis, accessory glands, and ducts
Females: ovaries, uterine tubes, uterus, and vagina
Sole purpose is to produce offspring

24. Major Organs

25. Life Functions
Organ systems work together to promote health and well-being of entire body. Must be able to provide eight functions necessary for living. A healthy body must …
HINT: these are all VERBS!

26. Maintain boundaries The “inside” remains distinct from the “outside.”
Examples include
a cell’s environment maintained by the cell membrane
the integumentary system protecting organs from desiccating (drying out), from bacteria and viruses, from heat and sunlight, and from chemicals

27. Move Muscle movement is necessary for
Locomotion: getting us from one place to another, or for moving muscle for safety (hot stove)
Movement of substances: getting blood, food, and urine through their proper organs

28. Respond or be irritated
Ability to sense changes (from stimuli) and react to them
Ex: is automatically removing hand from broken glass (painful stimulus) that cuts – involuntary response
Ex: when decrease in oxygen levels detected (mountains), response is to increase breathing rate to obtain more oxygen

29. Digest
Breakdown of nutrients and absorption into blood for delivery to all body cells

30. Metabolize Chemical reactions within body cells to
Produce energy in form of ATP (adenosine triphosphate)
Make body structures like bones and muscles
Regulated mainly by hormones secreted by glands of endocrine system
testosterone

31. Excrete
Eliminate excreta (waste) from digestions and metabolic reactions
Urine
Feces

32. Reproduce Produce future generations…
of identical cells in cell division (repair or growth)
of entire organism

33. Grow Increasing cell size and number
Must make more cells faster than cells die

34. HINT: these are all NOUNS!
Survival needs
In order to maintain the eight functions for living, the human body must have the following items:
Nutrients
Chemicals for energy and cell building
Carbohydrates
Proteins
Lipids
Vitamins
Minerals

35. Oxygen
Required for chemical reactions
Cellular respiration

36. Water
60-80% of body weight
Necessary for metabolic reactions

37. Basal body temperature
98.6°F or 37°C
Atmospheric pressure
Standard atmospheric pressure (on earth at sea level is 760 mmHg or inHg)

38. Homeostasis
Maintenance of a stable internal environment = a dynamic state of equilibrium
Homeostasis must be maintained for normal body functioning and to sustain life
When needs are being adequately met, body is functioning smoothly, body demonstrates homeostasis
All organ systems partake in maintaining homeostasis

39. Homeostatic imbalance – a disturbance in homeostasis sets off chain reaction of events
Stimulus
Produces change in variable
Detection
Change is detected by receptor
Input
Information is sent from receptor to control center
Output
Control center decides what action or response should be taken
Response
Action or response feeds back to influence magnitude of stimulus and returns variable to homeostasis

40. Overview of Homeostasis

41. The body communicates chiefly through nervous and endocrine systems
Nervous uses electrical signals delivered by nerves
Endocrine system uses blood borne hormones
Factor being regulated is called the variable

42. All homeostatic control mechanisms have at least three components
Receptor
Responds to changes in the environment (stimuli)
Sends information to control center via afferent pathway
Afferent approaches control center
Control center
Determines set point at which variable should be maintained
Analyzes information
Determines appropriate response
Effector
Provides a means for response to the stimulus
Desired response flows along efferent pathway
Efferent exits control center

43. Most homeostatic control mechanisms are negative feedback mechanisms
Includes most homeostatic control mechanisms
Shuts off the original stimulus, or reduces its intensity
Works like a household heating system with set point of 72°F
If it’s too cold, will heat it up by turning on heater
If it’s too warm, will shut off heater until it levels off

44. Hypothalamus, located in brain, regulates body temperature

45. If stimulus produces desired effect, and body needs it to increase in action, a positive feedback results
Positive feedback
Increases the original stimulus to push the variable even farther away from set point
In the body this only occurs in blood clotting, birth of a baby, breastfeeding, and protein digestion
Cut on hand = stimulus (wasn’t there prior and is not part of body set-point)
Factor in blood starts to form blood clots
Body wants MORE blood clots so positive feedback mechanism takes over
MORE blood clotting factors are in play until wound heals

46. Homeostasis is SO important that most disease is a result of homeostatic imbalance
As we age, body organs become less efficient, and internal conditions less stable
Events put us at increased risk for illness and produce changes associated with aging
Ex: elastin in connective tissue of skin makes it able to resume shape after stretching, like a rubber band
As we age, elastin production decreases and/or breaks down, so skin loses ability to resume shape

48. Anatomical Language
Can’t always describe body as left and right or top and bottom because so many protrusions and bends. Have specific terminology to describe locations of the body.
Exact terms are used for
Positions
Directions
Regions
Structures

49. Positions
Initial point of reference is always the standard position called anatomical position regardless of position body happens to be in (like sitting)
Body standing erect
Feet parallel
Arms hanging at sides, palms facing forward
Two major positions:
Anterior – front of body in anatomical position
Posterior – back of body in anatomical position

50. Regions Anterior body landmarks
See page 13 of book (don’t need to know for test)

51. Posterior body landmarks
See page 13 of book (don’t need to know for test)

52. Directions Used to describe body structure is in relation to another.
Superior – toward head
Inferior – away from head; below
Anterior – toward or at front; in front of
Posterior – toward or at back; behind
Medial – toward or at midline
Lateral – away from midline
Intermediate – between a more medial and more lateral structure
opposites
opposites
opposites

53. Superficial – toward or at body surface
Proximal – close to origin of body part or point of attachment of a limb to the body trunk
Distal – farther from origin of a body part or point of attachment of a limb to the body trunk
Superficial – toward or at body surface
Deep – away from body surface; more internal
Supine – lying face upwards
Prone – lying face down
opposites
opposites
opposites

56. Structures
Planes and sections
Midsagittal
Frontal
Transverse

57. Body cavities