An overview of the human body systems

1. C H A P T E R 1 – T H E H U M A N B O D Y : A N
O R I E N T A T I O N
ANATOMY & PHYSIOLOGY

2. A N O V E R V I E W O F A N A T O M Y A N D
P H Y S I O L O G Y
CHAPTER 1

3. Let’s start with the basics
 anatomy: the study of the structure and shape of the
body and its parts and their relationships to one another
 gross anatomy: the study of large body structures (human body)
 microscopic anatomy: the study of body structures too small to be
seen with the naked eye (cells and tissues)
 physiology: the study of how the body and its parts work
or function

4. They are ALWAYS related
 The parts of the body form a well-organized unit
 You want to view the body in terms of structure and
function
 Cardiovascular system

5. W H Y M U S T W E U S E L E V E L S O F
O R G A N I Z A T I O N ?
LEVELS OF ORGANIZATION

6. The basics
 Each level contains progressively larger structures
 The structure in each level is composed of structures
from the preceding level

7. Level 1 – Chemical Level
 Smallest level of organization
 From atoms up to molecules
 atoms: the building blocks of all matter
 ex. H, H2O

8. Level 2 – Cellular Level
 cells: the smallest unit of all living things
 Ex. neuron

9. Level 3 – Tissue Level
 tissue: consist of groups similar cells that have a
common function
 4 basic types (epithelial, connective, muscular,
neural)
 ex. neural tissue

10. Level 4 – Organ Level
 organ: structure composed of two or more tissues
types that performs a specific function
 at this level, extremely complex functions become
possible
 ex. brain

11. Level 5 – Organ System Level
 organ system: a group of organs that work together
to accomplish a common purpose
 ex. CNS

12. Level 6 – Organismal Level
 Organismal Level
 organism: an individual living thing composed of
multiple organ systems working together
 Humans use 11 organ systems

13. A N O V E R V I E W
THE HUMAN ORGAN
SYSTEMS

14. 11 Organ Systems
 We will examine each system in more detail later in
the year
 Look at both the structures involved and how each of
these structures function both independently and
together
 Take note how the organ systems are interrelated

15. Integumentary System
 structure: skin (external covering of the body)
 function:
 1. waterproofs the body
 2. cushions and protects deeper tissues from injury
 3. excretes salts and urea during perspiration
 4. helps regulate body temperature

16. Skeletal System
 structure: bones, cartilages,
ligaments, joints
 function:
 1. supports the body
 2. provides a framework for
skeletal muscles
 3. protects some organs
 4. performs hematopoiesis
 hematopoiesis: formation of
blood cells

17. Muscular System
 structure: skeletal muscles
 function: to contract and to
allow movement
 viewed as the “machines” of
the body
 allows for locomotion,
maintains posture,
produces heat, etc.

18. Nervous System
 structure: brain, spinal cord, nerves, sensory receptors
(body’s fast-acting control system)
 function:
 1. respond to external stimuli
 2. respond to internal stimuli
 assesses information and responds by activating the
appropriate body effectors (muscles or glands)

19. Endocrine System
 structure: pituitary, thyroid, parathyroids, adrenals,
thymus, and pineal glands, pancreas, ovaries/testis
 function:
 1. controls body activities (slower than the nervous
system)
 2. produce and release hormones

20. Cardiovascular System
 structure: heart and blood vessels
 function:
 1. carries oxygen, nutrients,
hormones, and other substances to
and from tissue cells where
exchanges are made
 2. WBCs help protect the body from
foreign invaders (bacteria, toxins,
tumor cells)

21. Respiratory System
 structure: nasal passages,
pharynx, larynx (vocal cords),
trachea, bronchi and lungs,
 function:
 1. keeps body constantly supplied
with oxygen
 2. removes carbon dioxide from
the body
 thin walls of the air sacs allows
gases to be transported to and
from the lungs

22. Lymphatic System
 structure: lymphatic vessels,
lymph nodes, spleen, tonsils
 function: 1. returns fluid
leaked from the blood back to
the blood vessels
 2. help cleanse the blood and
house cells involved in
immunity
 complements the
cardiovascular system

23. Digestive System
 structure: (mouth -> anus)
 oral cavity (mouth), esophagus, stomach, small and large
intestines, rectum, anus
 function:
 1. breakdown food
 2. deliver products to the blood for dispersal to the body
cells
 3. reclaim water (large intestines)
 liver is a digestive organ because it produces bile, which
helps break down fats
 pancreas delivers digestive enzymes to the small
intestines, functionally a digestive organ

24. Diagram of the Digestive System

25. Urinary System (Excretory System)
 structure: kidneys, ureters,
bladder, urethra
 function:
 1. removes Nitrogen-containing
wastes from the blood in the form
of urine
 2. helps maintain salt and water
balance (electrolyte)
 3. regulates the acid-base balance
of the blood

26. Reproductive System
 structure:
 in males: testes, scrotum, penis, accessory glands,
and duct system
 in females: ovaries, uterine tubes, uterus, vagina
 function: to produce offspring

27. WHAT THINGS MUST HAPPEN IN
INDIVIDUAL ORGAN SYSTEMS AND
BETWEEN MULTIPLE ORGAN
SYSTEMS TO ALLOW THE HUMAN
BODY TO FUNCTION?
NECESSARY LIFE
FUNCTIONS

28. The basic idea
 all organisms must use and maintain necessary life
functions
 organ systems are interdependent
 it is important to establish which organ systems are
most directly related to each life function

29. What must happen:
 1. Maintain Boundaries
 2. Movement
 3. Responsiveness
 4. Digestion
 5. Metabolism
 6. Excretion
 7. Reproduction
 8. Growth

30. Maintaining Boundaries
 Maintaining Boundaries
 every living organism needs to maintain boundaries to
keep “insides” distinct from “outsides”
 every individual cell has a membrane (most semi- or
selectively permeable) (microscopic anatomy)
 the body is enclosed by the Integumentary system
(gross anatomy)
 protects internal organs from drying out
 protects internal organs from bacteria
 protects body from the damaging effects of heat, sunlight,
chemical substances, and the external environment

31. Movement
 movement: all activities promoted by the muscular
system
 muscular system provides the muscles
 skeletal system provides the bones the muscles pull
on as they work
 movement also occurs when substances are
propelled through the internal organs of the
cardiovascular, digestive and urinary systems

32. Responsiveness
 responsiveness: (also called irritability) is the ability
to sense changes in the environment and react to
them
 the nervous system is the most responsible for
responsiveness
 however, all body cells are irritable to some extent.

33. Digestion
 digestion: the process of breaking down ingested
food into simple molecules that can be absorbed into
the blood
 in the complex body this is performed by the
digestive system

34. Metabolism
 metabolism: a broad term that refers to all
chemical reactions that occur within body cells
 includes:
 breaking down complex molecules into simpler ones
 using Oxygen and nutrients to produce molecules of ATP
(adenosine triphosphate, the energy-rich molecules that
power cell activities)
 depends on the respiratory, digestive, and
cardiovascular systems
 mainly regulated by hormones secreted by the
glands on the endocrine system

35. Excretion
 excretion: the process of removing excreta (wastes)
from the body
 nonuseful substances produced during digestion and
metabolism must be removed
 several organ systems participate in excretion,
including the digestive and urinary systems

36. Reproduction
 reproduction: the production of offspring
 can occur at both the cellular and organismal levels
 ex. mitosis in cells, human reproduction
 task of the reproductive system, regulated precisely
by the hormones of the endocrine system

37. Growth
 growth: an increase in size, usually accomplished by
an increase in the number of cells
 for growth to occur, cell-constructing activities must
occur at a faster rate than cell-destroying ones

38. W H A T A R E T H E B A S I C S U B S T A N C E S
N E C E S S A R Y F O R H U M A N S U R V I V A L ?
SURVIVAL NEEDS

39. Survival Needs
 several factors necessary for maintaining life
 nutrients, Oxygen, water, appropriate temperature
and atmospheric pressure
 must be present in appropriate amounts; too much
or too little may be equally harmful

40. Survival Needs
 1. Nutrients
 body takes in through food
 contain the chemicals used for energy and cell building
 proteins, carbohydrates, etc
 2. Oxygen
 the chemical reactions that release energy from foods
require Oxygen
 approximately 20% of the air we breathe is Oxygen
(20.95%)

41. Survival Needs
 3. water
 60-80 % body weight, 65-75% in muscle, only 10% in fat
 50-60% in most people, women have a lower percentage
due to higher body fat
 single most abundant chemical substance in the body
 provides the fluid base for body secretions and excretions
(secretion is an active process/particle movement,
excretion is a passive process/waste removal)
 chiefly ingested from foods and liquids
 lost by evaporation and body excretions

42. Survival Needs
 4. body temperature
 must be maintained around 37°C or 98.6°F
 as temperature drops, metabolic reactions slow until
they stop
 as temperature rises, metabolic reactions speed up
and can proceed too rapidly
 at either extreme, death will occur
 most body heat is generated by the activity of skeletal
muscles

43. Survival Needs
 5. atmospheric pressure
 atmospheric pressure: the force exerted on the
surface of the body by the weight of the air
 breathing and the exchange of oxygen and carbon
dioxide in the lungs depend on appropriate
atmospheric pressure

44. WHAT IS HOMEOSTASIS?
WHY IS IT IMPORTANT?
HOMEOSTASIS

45. Homeostasis
 homeostasis: a state of body equilibrium or stable
internal environment of the body
 literally means “unchanging”
 (homeo = the same, stasis = standing still)
 dynamic state of equilibrium
 ex. blood pressure, waste accumulation, body
temperature

46. Homeostasis
 communication is key, and is mainly controlled by
the nervous and endocrine systems
 nerves
 bloodborne hormones
 The factor being regulated by homeostasis is the
variable

47. Homeostasis
 all homeostatic control mechanisms have at least
three components:
 1. A receptor
 2. A control center
 3. An effector

48. A receptor
 a receptor that responds to environmental changes
 some type of sensor that monitors and responds to
change
 stimulus: the change (pl. stimuli)
 sends information(input) to the second element (the
control center) along the afferent pathway
 the afferent pathway approaches the control center

49. A control center
 a control center that assesses changes
 determines the level at which a variable is to be
maintained
 analyzes the information it receives
 determines the appropriate course of action or response

50. The effector
 provides the means for the control center’s response
(output) to the stimulus
 information flows from control center to the effector
along the efferent pathway
 efferent information exits from the control center
 the results of the response feedback to influence the
stimulus
 either depresses (negative feedback) or enhances
(positive feedback)

51. Negative Feedback Systems
 Negative feedback mechanisms: the
net effect of the response to the
stimulus is to shut off the original
stimulus or reduce its intensity
 most homeostatic control
mechanisms
 ex. Home thermostat
 hypothalamus in the body
 also includes heart rate, blood
pressure, breathing rate, blood
nutrient levels

52. Positive Feedback Systems
 Positive feedback mechanisms: tend to increase the
original disturbance (stimulus) and to push the
variable farther from its original value
 rare in the body
 events that occur explosively
 ex. Blood clotting, birth

53. Homeostatic Imbalance
 Homeostasis is so important that most diseases can
be regarded as homeostatic imbalances
 as age increases, organ function decreases, and the
risk of disease/homeostatic imbalance as increases