Human physiology is the study of the function of body parts. this an introductory lecture that introduces learners to the exciting discovery of an exciting subject in the study of medicine.

1. HUMAN PHYSIOLOGY
Mr. KUNDA

2. CONTENT
0. Introduction
1. Body Fluid
Compartments
2. Composition of Body
Fluids

3. Introduction
• Concept “physiology” (physio: nature; logy: study of) is the
science of body functions (how the body parts work).
• E.G.,: why does the heart automatically beat?
• Goal of physiology: to explain the physical and chemical
factors that are responsible for the origin, development, and
progression of life.
• Each type of life has its own functional characteristics.

4. Introduction cont.
• Therefore, Human physiology is:
• The scientific study of the chemistry and physics of the structures
of the human body and the ways in which they work together to
support the functions of life.
Or
• The scientific study of how the body systems work, and the ways
in which their integrated activities maintain life and health of the
individual.

5. Introduction cont.
The History of Physiology
• Aristotle emphasized the relationship between structure and
function
• Galen was the first to perform experiments to understand the
function of the body; so known to be father of physiology
• The first “physiologist” of the world, in the modern sense, was
William Harvey. In the 17thcentury William Harvey first
describes the circulatory system and its interaction with the
body
• Claude Bernard (1813-1878) propounded the concept of milieu
interieur or internal environment and established physiology as
the scientific basis of medicine.

6. Introduction cont.
Field of Physiology
• Physiology can be divided into viral physiology, bacterial
physiology, cellular physiology, plant physiology, human
physiology, and many more subdivisions.
• Human physiology is the science of studying the rule of
physiological functions in human body.

7. Introduction cont.
• Knowledge gain and the understanding of this course is
fundamental to your career in the health professions, and it will
also benefit your own health as well as in many other aspect of
your life.
• E.g: - help you make healthful choices and prompt you to take
appropriate action when signs of illness arise.

8. Introduction cont.
• Help you understand news about nutrition, medications, medical
devices, and procedures, genetic or infectious diseases.
• Can help you to be a better caregiver, parent, spouse, partner,
friend, or colleague.

9. Introduction cont.
Physiology Vs Anatomy:
• Scientific study of the body’s functions
Vs
• Scientific study of the body’s structure.

10. Introduction cont.
Levels of structural organization
From the smallest to the largest living structural, there
are six levels of organization which help to understand
anatomy and physiology:
Chemical Cellular Tissue Organ System
Organismal
level.

11.  Chemical level: This is the very basic level of structural
organization and includes atoms, the smallest units of matter that
participate in chemical reactions, and molecules, two or more
atoms joined together.
• Examples: atoms: O, C, H; molecules: DNA, H2O
Introduction cont.
Levels of structural organization

12.  Cellular level: Molecules combine to form cells, the basic
structural and functional units of an organism. Cells are the
smallest living units in the human body.
• The number: very large.
Example, an adult person ≈ 100 trillion cells.
• Among the many kinds of cells in the body are muscle cells,
nerve cells, and epithelial cells.
Introduction cont.
Levels of structural organization

13.  Tissue level: Tissues are groups of cells and the materials
surrounding them that work together to perform a particular
function.
• Four basic types of tissue in the body: epithelial tissue,
connective tissue, muscular tissue, and nervous tissue.
 Organ level: Organs are structures that are composed of two or
more different types of tissues. They have specific functions and
usually have recognizable shapes.
• Examples: stomach, skin, bones, heart, liver, lungs, and brain.
Introduction cont.
Levels of structural organization

14.  System level = organ-system level : A system consists of related
organs with a common function.
• Example: digestive system.
• An organ may be part of more than one system. The pancreas, for
example, is part of both the digestive system and the hormone-
producing endocrine system.
 Organismal level: An organism refers to all the parts (system) of
the human body functioning together.
Introduction cont.
Levels of structural organization

15. Introduction cont.
Levels of structural organization
• The human body has eleven
systems:
• Integumentary system
• Musculoskeletal system,
• Nervous system,
• Endocrine system,
• Cardiovascular system,
• Digestive system,
• Urinary system,
• Lymphatic system and
• Immunity
• Respiratory system,
• Reproductive systems.

16. Levels of Structural Organization

17. Introduction cont.
The Eleven Systems of the Human Body and their Main Functions

18. Introduction cont.
The Eleven Systems of the Human Body and their Main Functions

19. Introduction cont.
The Eleven Systems of the Human Body and their Main Functions

20. Introduction cont.
The Eleven Systems of the Human Body and their Mains Functions

21. Introduction cont.
The Eleven Systems of the Human Body and their Mains Functions

22. Introduction cont.
The Eleven Systems of the Human Body and their Mains Functions

23. Introduction cont.
Basic Life Processes
• Six most important life processes distinguish organisms or living
things, from nonliving:
1. Metabolism is the sum of all the chemical processes that occur
in the body.
• One phase of metabolism is catabolism (catabol: throwing
down; ism: a condition), the breakdown of complex chemical
substances into simpler components.

24. • The other phase of metabolism is anabolism (anabol: a raising
up), the building up of complex chemical substances from
smaller, simpler components.
• Axample: digestive processes catabolize (split) proteins in food
into amino acids. These amino acids are then used to anabolize
(build) new proteins that make up body structures such as
muscles and bones.
Introduction cont.
Basic Life Processes

25. 2. Responsiveness is the body’s ability to adjust to changes in its
internal and external environments.
• Example:
- moving toward sources of food and water and away from
perceived dangers are responses to external stimuli.
- Changes in an organism’s internal environment, such as
increased body temperature, can cause the responses of
sweating and the dilation of blood vessels in the skin in order to
decrease body temperature.
Introduction cont.
Basic Life Processes

26. 3. Movement includes motion of the whole body, individual
organs, single cells, and even tiny structures inside cells.
• Example:
- the coordinated action of leg muscles moves your whole body
from one place to another when you walk or run.
- After eating a meal that contains fats, your gallbladder
contracts and squirts bile into the gastrointestinal tract to aid in
the digestion of fats.
Introduction cont.
Basic Life Processes

27. 4. Growth is an increase in body size that results from an increase
in the size of existing cells, an increase in the number of cells, or
both.
In addition, a tissue sometimes increases in size because the
amount of material between cells increases.
• Example: in a growing bone, mineral deposits accumulate
between bone cells, causing the bone to grow in length and
width.
Introduction cont.
Basic Life Processes

28. 5. Differentiation is the development of a cell from an
unspecialized to a specialized state.
Also through differentiation, a fertilized egg (ovum) develops
into an embryo, and then into a fetus, an infant, a child, and
finally an adult.
Introduction cont.
Basic Life Processes

29. 6. Reproduction refers either to the formation of new cells for
tissue growth, repair, or replacement, or to the production of a
new individual.
• When the life processes cease to occur properly, the result is
death of cells and tissues, which may lead to death of the
organism.
Introduction cont.
Basic Life Processes

30. 1. BODY FLUID COMPARTMENTS

31. Objectives
• Explain the importance of water in the body
• Identify the body’s main fluid compartments
• Compare the locations of intracellular fluid (ICF) and extracellular fluid
(ECF) of the body.
• Describe the sources of water and solute gain and loss.

32. Body Fluid Compartments
• In the average young adult male is made up:
18% of the body weight is protein and related substances,
7% is mineral,
15% is fat and .
The remaining 60% is water.

33. Body Fluid Compartments
• Hence, human beings are mostly water, ranging from :
 about 75% of total body mass in infants to
about 55%–60% in lean adults men and women,
to as low as 45% in old age.
• The percent of body water is a function of age and gender.

34. Body Fluid Compartments
• The percent of body water changes with development, because
the proportions of the body given over to each organ and to
muscles, fat, bone, and other tissues change from infancy to
adulthood.
• The brain and kidneys have the highest proportions of water,
which composes 80–85% of their masses. In contrast, teeth have
the lowest proportion of water, at 8–10%.

35. Body Fluid Compartments

36. Body Fluid Compartments
• Body fluids are present in two main compartments:
the intracellular fluid (ICF) and
the extracellular fluid (ECF)
• The intracellular fluid (ICF) compartment (intra = within) or cytosol,
is the system that includes all fluid enclosed in cells by their plasma
membranes.
• This compartment contains about two-thirds (40%) of body fluid

37. Body Fluid Compartments
• The extracellular fluid (ECF) compartment (extra = outside) is outside
cells and includes all other body fluids. This extracellular fluid is in
constant motion throughout the body.
• In the extracellular fluid are the ions and nutrients needed by the cells to
maintain cell life.
• It represents the other third (20%) of body fluid.

38. Body Fluid Compartments
• The ECF has two primary constituents:
the plasma: fluid component of the blood; it represents about
20% of the ECF, and
the interstitial fluid (IF) (inter = between): fluid that surrounds all
cells not in the blood; it represents about 80% of the ECF.

39. Body Fluid Compartments
• Other extracellular fluids that are grouped with interstitial fluid
include:
lymph in lymphatic vessels;
cerebrospinal fluid in the nervous system;
synovial fluid in joints;
aqueous humor and vitreous body in the eyes;
endolymph and perilymph in the ears; and
pleural, pericardial, and peritoneal fluids between serous membranes.

40. Body Fluid Compartments

41. Body Fluid Compartments

42. • ICF: 2/3 of TBW
• ECF: 1/3 of TBW
- Plasma: 20%
- IF: 80%
Body Fluid Compartments

43. Body fluid volumes in a healthy 70-kg
adult male
Compartment Volume Subdivisions
Intracellular fluid, ICF (2/3
of TBW)
28 L -
Extracellular fluid, ECF;
1/3 of TBW
14 L 10.5 L
(Interstitial fluid)
3.5 L
(Plasma)
Total body water (TBW);
60% of body weight
42 L -

44. Body Fluid Compartments
• Differences Between Extracellular and Intracellular Fluids.
The extracellular fluid contains large amounts of sodium, chloride,
and bicarbonate ions plus nutrients for the cells, such as oxygen,
glucose, fatty acids, and amino acids.
It also contains carbon dioxide that is being transported from the cells to
the lungs to be excreted, plus other cellular waste products that are
being transported to the kidneys for excretion.

45. Body Fluid Compartments
The intracellular fluid differs significantly from the extracellular fluid;
specifically, it contains large amounts of potassium, magnesium, and
phosphate ions instead of the sodium and chloride ions found in the
extracellular fluid.
• Special mechanisms for transporting ions through the cell membranes
maintain the ion concentration differences between the extracellular and
intracellular fluids.

46. Body Fluid Compartments
• Extracellular fluid is transported through all parts of the body in
two stages:
The first stage is movement of blood through the body in the
blood vessels, and the
second is movement of fluid between the blood capillaries and
the intercellular spaces between the tissue cells.

47. • Two general “barriers” separate ICF, IF, and blood plasma:
The plasma membrane of individual cells (or cell
membrane): separates ICF from the surrounding IF.
• It therefore regulates the passage of materials between the IF and the ICF.
Body Fluid Compartments cont.

48. • The cell membrane is a selectively permeable barrier: It allows some
substances to cross but blocks the movement of other substances.
• In addition, active transport pumps work continuously to maintain
different concentrations of certain ions in the cytosol and IF.
Body Fluid Compartments cont.

49. Blood vessel walls: divide the IF from blood plasma.
• Only in capillaries, the smallest blood vessels, are the walls thin enough
and leaky enough to permit the exchange of water and solutes between
blood plasma and IF.
Body Fluid Compartments cont.

50. Sources of Body Water Gain and Loss
• The body can gain water by two ways:
–Ingestion and
–metabolic synthesis
 Ingestion: the main sources of body water are ingested liquids (about 1600
mL) and moist foods (about 700 mL) absorbed from the gastrointestinal
(GI) tract, which total about 2300 mL/day.
Body Fluid Compartments cont.

51.  metabolic synthesis: produces water in the body mainly when electrons
are accepted by oxygen during aerobic cellular respiration and to a smaller
extent during dehydration synthesis reactions.
Metabolic water gain accounts for only 200 mL/day.
• Daily water gain from these two sources totals about 2500 mL.
• Normally, body fluid volume remains constant because water loss = water
gain.
Body Fluid Compartments cont.

52. • Water loss occurs in four ways: each day,
–the kidneys excrete about 1500 mL in urine,
–the skin evaporates about 600 mL (400 mL through insensible
perspiration, sweat that evaporates before it is perceived as
moisture, and 200 mL as sweat),
–the lungs exhale about 300 mL as water vapor, and
–the gastrointestinal tract eliminates about 100 mL in feces.
Body Fluid Compartments cont.

53. • In women of reproductive age, additional water is lost in menstrual flow.
• On average, daily water loss totals about 2500 mL.
• The amount of water lost by a given route can vary considerably over time.
For example, water may literally pour from the skin in the form of sweat
during strenuous exertion. In other cases, water may be lost in diarrhea
during a GI tract infection.
Body Fluid Compartments cont.

54. • Sources of Body Water Gain and Loss
Body Fluid Compartments cont.

55. 2. COMPOSITION OF BODY FLUIDS

56. • List the main function of body fluid
• Compare the electrolyte composition of the three major fluid
compartments: plasma, IF, and ICF.
• Discuss the functions of sodium, chloride, potassium, bicarbonate,
calcium, phosphate, and magnesium ions, and explain how their
concentrations are regulated.
Objectives

57. • Facilitate the transport of nutrients, hormones, proteins, and other
molecules into the cells
• Aid in the removal of cellular metabolic waste products
• Provide the medium in which cellular metabolism takes place
• Regulate body temperature
• Provide lubrication of musculoskeletal joints
• Act as a component in all body cavities (pericardial, pleural, spinal,
peritoneal fluid)
Composition of Body Fluids
Function of body fluids

58. • The body fluids are composed of electrolytes and non-electrolytes.
• Electrolytes: substances whose molecules dissociate into ions (charged
particles) when placed into water
–Cations: ions positively charged
–Anions: ions negatively charged
Composition of Body Fluids

59. • The compositions of the two components of the ECF (plasma and IF) are
more similar to each other than either is to the ICF.
• The primary body electrolytes are sodium, potassium, chloride,
calcium, magnesium, phosphorus, hydrogen, bicarbonate.
Composition of Body Fluids cont.

60. • Blood plasma has high concentrations of sodium, chloride, bicarbonate,
and protein.
• The IF has high concentrations of sodium, chloride, and bicarbonate, but a
relatively lower concentration of protein.
• In contrast, the ICF has high concentrations of potassium, phosphate,
magnesium, and protein.
Composition of Body Fluids cont.

61. • Overall:
–the ICF contains high concentrations of potassium (K+) and
phosphate (HPO4
2−), whereas
–the ECF (plasma and IF) contains high concentrations of
sodium (Na+) and chloride (Cl) and bicarbonate (HCO3
).
Composition of Body Fluids cont.

62. Composition of Body Fluids cont.

63. Interstitial Intracellular
Plasma, fluid, fluid,
Ion mmoles/L mmoles/L mmoles/L
Cations
Na+
142.0 145.1 10.0
K+
4.3 4.4 140.0
Ca2+
(ionized) 2.5 2.4 1.0
Mg2+
(ionized) 1.1 1.1 17
Others 4.0
Total 154 153 168
Anions
Cl-
114.0 117.4 4.0
HCO3
-
24.0 27.1 7.0
HPO4
2-
, H2PO4
-
1.0 1.2 40.0
Proteins 1.5 0.1 3.0
Other 10.0 6.2 84.0
Total 154 153 138
Composition of Body Fluids cont.
Approximate ionic composition of the
body water compartments

64. • Cations
• Sodium
–Range: 135-145 mEq/L
–Normal daily requirement: 1-2 mEq/kg/day
–Chief extracellular cation
• Potassium
–Range: 3.5-5.0 mEq/L
–Normal daily requirement: 0.5 – 0.8 mEq/kg/day
–Chief intracellular cation
Composition of Body Fluids cont.
Normal Plasma Ranges of Electrolytes

65. • Calcium (8.0-10.5 mEq/L)
• Magnesium (1.5-2.5 mEq/L)
• Anions
• Chloride (95-105 mEq/L)
• Bicarbonate (24-30 mEq/L)
• Phosphate (2.5-4.5 mEq/L)
• Sulfate (1.0 mEq/L)
• Organic Acids (Lactate) (2.0 mEq/L)
• Total Protein (6.0-8.4 mEq/L)
Composition of Body Fluids cont.
Normal Plasma Ranges of Electrolytes

66. • The ions formed when electrolytes dissolve and dissociate serve four
general functions in the body:
1. Ions control the osmosis of water between fluid compartments (Maintain
osmolality of body fluid compartments), because they are largely
confined to particular fluid compartments and are more numerous than
non-electrolytes.
2. Ions regulate the acid–base balance required for normal cellular
activities.
3. Ions carry electrical current, which allows production of action
potentials and graded potentials.
4. Several ions serve as cofactors needed for optimal activity of enzymes.
Composition of Body Fluids cont.

67. ASSIGNMENT 1
1. Explain in detail how body fluids are measured
2. How would you measure the following?
A. IF volume
B. ICF volume
3. Outline the relationship between blood volume and plasma volume.
4. Define Lean body mass (LBM) and state how it is calculated
5. 100 mg of sucrose is injected into a 70 kg man. The plasma sucrose level after mixing is
0.01 mg/ml. If 5 mg has been metabolized during this period, then, what is the ECF
volume?
6. In a healthy 70 kg adult male, plasma volume was found to be 3000 ml. Hematocrit was
40%. Calculate his blood volume?
7. In a healthy adult male weighing 70 kg, total body water (TBW) was measured to be 42
L. What is his lean body mass (LBM)? What is his fat mass?
The assignment should be HAND WRITTEN. Due date 9th August, 2022. TIME 14HRS.

68. END