introduction to the physiology

1. INTRODUCTION TO
PHYSIOLOGY
DR OLUFUNKE ONAADEPO. MBBS.MSc PhD

3. Introduction-What is physiology
•Physiology – scientific study of the normal
function in living systems. i.e
functions and mechanisms in a living system
•A branch of biology, its focus is in how
organisms, organ systems, organs, cells, and
biomolecules carry out the chemical or physical
functions that exist in a living system
•An academic discipline, A branch of science .A
branch of biology

4. Introduction-What is physiology
• There are many ways to categorize the subdisciplines of physiology:
• based on the taxa studied: human physiology, animal
physiology, plant physiology, microbial physiology, viral physiology
• based on the level of organization: cell physiology, molecular
physiology, systems physiology, organismal physiology, ecological
physiology, integrative physiology
• based on the process that causes physiological
variation: developmental physiology, environmental
physiology, evolutionary physiology
• based on the ultimate goals of the research: applied physiology (e.g.,
medical physiology), non-applied (e.g., comparative physiology)

5. •Physiological state is the condition of normal function.
•In contrast, pathological state refers to abnormal
conditions, including human diseases.

6. Why is physiology important for medical
students?
• Physiology is the foundation of medicine, it is
important for medical students to understand the
normal and abnormal functions of humans.
• It means learning physiology will improve your
concepts of pathology and other important subjects
you learn during medical school

7. Physiology and other biological sciences
• Physiology and medicine
• Physiology is an experimental scientific discipline and
is of central importance in medicine and related
health sciences (nursing, anesthesia, clinical
psychology, dentistry, physiotherapy
• . It provides a thorough understanding of normal body
function, enabling more effective treatment of
abnormal or disease states

8. Physiology and other Biological Sciences
• Anatomy is closely related to physiology because it deals
with the structure of living organisms. Whereas physiology
focuses on the functions of these structures, anatomy
provides information about the physical structures
themselves.
• For example, an anatomist might study the structure and
arrangement of muscle fibers in a particular muscle, while a
physiologist might study how that muscle contracts and
generates force

9. Physiology and other biological sciences
• The Physiology & Pharmacology
discipline encompasses the study of fundamental
mechanisms that underlie cellular and systems level
function and dysfunction.
• In addition, this discipline examines how drugs
influence these systems, with the ultimate goal being
to better treat human disease.

10. Physiology and other Biological Sciences
• Biochemistry is the science that deals with the
chemical processes that occur within living organisms,
including the synthesis and breakdown of molecules
such as proteins, carbohydrates, and lipids
• Physiology helps us understand the chemical aspects
of biological processes such as digestion, hormonal
action, and muscle contraction-relaxation
• .
• .

11. Physiology and other Biological Sciences
•Molecular biology is another field that is closely related
to physiology. Molecular biology deals with the study of
biological molecules, such as DNA and RNA, and the
processes that govern their replication, transcription,
and translation.
• Physiology is essential for a complete understanding of
molecular biology .

12. Physiology and other Biological Sciences
• Genetics is also closely related to physiology. Genetics
deals with the study of heredity and the transmission
of genetic information from one generation to the
next.
• physiological is important in understanding of
genetics is essential for understanding the
mechanisms that underlie hereditary

13. Physiology and other Biological Sciences
• Ecology is another field that is related to physiology, albeit in a
more indirect way. Ecology deals with the study of the interactions
between organisms and their environment, and how these
interactions shape the distribution and abundance of different
species.
• Because physiological processes play a key role in determining an
organism's ability to survive and reproduce in its environment, an
understanding of physiology is essential for understanding
ecological patterns and processes..

14. Branches of physiology by organism
• According to the classes of organisms, the field can
be divided into
• Medical physiology, (Human physiology)
• animal physiology,
• plant physiology,
• cell physiology, and
• comparative physiology

15. Approach to study of medical physiology
•The 2 approaches to physiology are the following
•1) Mechanistic approach
•2) Teleological approach

16. Approach to study of medical physiology
• The mechanistic approach in physiology
• explains HOW events occur
• An example the mechanistic approach in physiology
could be when you shiver
• How you shiver is because a drop in body
Temperature leads to signals for muscle contraction

17. Approach to study of medical physiology
• The teleological approach to physiology
• explains how a function fills a need, "WHY"
• An example of the teleological approach in physiology
could be when
• Why you shiver is because you need to keep warm

19. Cellular organization of the body
• 4 major tissue types are
• 1) muscle
2) epithelial
3) nervous
4) connective

24. Body systems
• Circulatory system consists of the-heart, blood, blood vessels
• Digestive system consists of the-mouth, pharynx, esophagus,
stomach, small intestine, large intestine, salivary glands, exocrine,
pancreas, liver, gall bladder
• Respiratory system consists of the-nose, pharynx, larynx, trachea,
bronchi, lungs
• Urinary system consists of the-kidneys, ureters, urinary bladder,
urethra
• Skeletal system consists of the-bones, cartilage, joints
• Muscular system consists of the-skeletal muscles
• Integumentary system consists of the-skin, hair, nails

25. Body systems
• Immune system consists of the-lymph nodes, thymus, bone marrow,
tonsils, adenoids, spleen, appendix, white blood cells, gut-associated
lymphoid tissue, and skin-associated lymphoid tissue
• Nervous system consists of the-brain, spinal cord, peripheral nerves,
special sense organs
• Endocrine system consists of the-all hormone-secreting tissues,
including hypothalamus, pituitary, thyroid, adrenals, endocrine
pancreas, gonads, kidneys, pineal, thymus, parathyroids, intestine,
heart, and skin
• reproductive system consists of the-Male: testes, penis, prostrate
gland, seminal vesicles, bulbourethral glands, and associated ducts
Female: ovaries, oviducts, uterus, vagina, breasts

26. The study of Medical physiology
• CELL PHYSIOLOGY- cell structure, function mechanism
of function-movements between cells homeostasis,
the body fluids
• SYSTEMIC PHYSIOLOGY- systemic review of the body
physiology

27. CELL PHYSIOLOGY
Animal Cell Definition
“An animal cell is a type of eukaryotic cell
that lacks a cell wall and has a true,
membrane-bound nucleus along with
other cellular organelles.

28. Cell Structure
• animal cells range in size from a few microscopic microns to a few
millimetres.
• The largest known animal cell is the ostrich egg, which can stretch
over 5.1 inches across and weighs about 1.4 kilograms. This is in
stark contrast to the neuron in the human body, which is just 100
microns across.
• The shape of animal cells also varies, with some being flat, others
oval or rod-shaped. There are also more intriguing shapes such as
curved, spherical, concave and rectangular. Most of the cells are
microscopic in size and can only be seen under the microscope.

29. Cell Structure
• As stated before, animal cells are eukaryotic cells with
a membrane-bound nucleus. Furthermore, these cells
exhibit the presence of DNA inside the nucleus.
• They also comprise other membrane-bound
organelles and cellular structures which carry out
specific functions necessary for a cell to function
properly

30. Cell Structure
•several basic functions of all cells are the following
•1) obtain nutrients and O2
2) make usable energy, Food + O2 --> CO2 + H2O +
energy
3) eliminate wastes
4) synthesize needed molecules
5) respond to environmental changes
6) control exchange of materials with the environment
7) transport molecules
8) reproduce

31. Cell Types
• There are numerous types of animal cells, each designed to serve specific
functions. The most common
• Skin Cells
• Melanocytes, keratinocytes, Merkel cells and Langerhans cells
• Muscle Cells
• Myocyte, Myosatellite cells, Tendon cells, Cardiac muscle cells
• Blood Cells
• Leukocytes, erythrocytes, platelet
• Nerve Cells
• Schwann cell, glial cells etc
• Fat Cells
• Adipocytes

32. Cell Structure

34. Cell Structure
•Though this animal cell diagram is not representative
of any one particular type of cell, it provides insight
into the primary organelles and the intricate internal
structure of most animal cells.
•Furthermore, it is easy to distinguish between a
plant and animal cell diagram just by inspecting the
presence or absence of a cell wall

35. Cell Structure
• Cell Structure
• Animal cells are generally smaller than plant cells. Another
defining characteristic is its irregular shape. This is due to the
absence of a cell wall. But animal cells share other cellular
organelles with plant cells as both have evolved from eukaryotic
cells.
• A typical animal cell comprises the following cell organelles:

36. Cell Structure
• Cell Membrane
• A thin semipermeable membrane
layer of lipids and proteins
surrounding the cell.
• Its primary role is to protect the
cell from its surrounding. Also, it
controls the entry and exit of
nutrients and other microscopic
entities into the cell.
• For this reason, cell membranes
are known as semi-permeable or
selectively permeable membranes.

37. Cell Structure
•Nucleus
•It is an organelle that
contains several other
sub-organelles such as
nucleolus, nucleosomes
and chromatins.
•It also contains DNA and
other genetic materials.

38. Cell Structure
• Nuclear membrane/envelope
• The nuclear membrane/envelop is a
double-layered structure that
encloses the contents of the
nucleus. The outer layer of the
membrane is connected to the
endoplasmic reticulum.
• Like the cell membrane, the nuclear
envelope consists
of phospholipids that form a lipid
bilayer.

39. Cell Structure
• The envelope helps to maintain the shape of the
nucleus and assists in regulating the flow of
molecules into and out of the nucleus
through nuclear pores.
• The nucleus communicates with the remaining of
the cell or the cytoplasm through several
openings called nuclear pores.
• Such nuclear pores are the sites for the exchange
of large molecules (proteins and RNA) between
the nucleus and cytoplasm.
• A fluid-filled space or perinuclear space is present
between the two layers of a nuclear membrane.

40. Cell Structure
• Nucleoplasm is the gelatinous substance within the
nuclear envelope.
• Also called karyoplasm, this semi-aqueous material is
similar to the cytoplasm and is composed mainly of
water with dissolved salts, enzymes, and organic
molecules suspended within.
• The nucleolus and chromosomes are surrounded by
nucleoplasm, which functions to cushion and protect
the contents of the nucleus.
• Nucleoplasm also supports the nucleus by helping to
maintain its shape. Additionally, nucleoplasm provides a
medium by which materials, such as enzymes
and nucleotides (DNA and RNA subunits), can be
transported throughout the nucleus. Substances are
exchanged between the cytoplasm and nucleoplasm
through nuclear pores.

41. Cell Structure
• Nucleolus
• Contained within the nucleus is a
dense, membrane-less structure composed
of RNA and proteins called the nucleolus.
• Some of the eukaryotic organisms have a nucleus
that contains up to four nucleoli.
• The nucleolus contains nucleolar organizers,
which are parts of chromosomes with
the genes for ribosome synthesis on them. The
nucleolus helps to
synthesize ribosomes by transcribing and
assembling ribosomal RNA subunits. These
subunits join together to form a ribosome during
protein synthesis.
• The nucleolus disappears when a cell undergoes
division and is reformed after the completion of
cell division.

42. Cell Structure
• The nucleus is the organelle that houses
chromosomes.
• Chromosomes consist of DNA, which
contains heredity information and
instructions for cell growth, development,
and reproduction.
• Chromosomes are present in the form of
strings of DNA and histones (protein
molecules) called chromatin.
• When a cell is “resting” i.e. not dividing,
the chromosomes are organized into long
entangled structures called chromatin.
• .

43. Cell Structure
• Nuclear Membrane
• It is a double-membrane
structure that surrounds
the nucleus.
• It is also referred to as
the nuclear envelope.

44. Animal Cell Structure
• Nucleopore
• They are tiny holes present
in the nuclear membrane
which are involved in the
movement of nucleic acids
and proteins across the
nuclear membrane.

45. Cell Structure
•Centrosome
•It is a small organelle
found near the nucleus,
which has a thick centre
with radiating tubules.
The centrosomes are
where microtubules are
produced.

46. Cell Structure
• Lysosome
•They are round organelles
surrounded by a membrane
and comprising digestive
enzymes which help in
digestion, excretion and in
the cell renewal process.

47. Cell Structure
• Cytoplasm
•A jelly-like material which
contains all the cell
organelles, enclosed within
the cell membrane.
•The substance found within
the cell nucleus, contained by
the nuclear membrane is
called the nucleoplasm.

48. Cell Structure
• Golgi Apparatus
• A flat, smooth layered, sac-
like organelle which is
located near the nucleus
and involved in
manufacturing, storing,
packing and transporting
the particles throughout the
cell.

49. Cell Structure
• Mitochondrion
• They are spherical or rod-
shaped organelles with a
double membrane.
• They are the powerhouse
of a cell as they play an
important role in
releasing energy.

50. Cell Structure
• Ribosome
• They are small organelles
made up of RNA-rich
cytoplasmic granules,
and they are the sites of
protein synthesis.

51. Cell Structure
•Endoplasmic Reticulum (ER)
•This cellular organelle is
composed of a thin, winding
network of membranous
sacs originating from the
nucleus.

54. END OF LECTURES
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