2. Levels of Structural Complexity of the body
• Chemical
• Cellular
• Tissue
• Organ
• System
• Organism
3. • Chemical Level
• Atoms and molecules essential for life
• Atoms: C, H, O, N, Ca, K, Na
• Molecules: proteins, carbohydrates, fats,
vitamins, water
• Cellular Level
• Cells are the basic structural and functional units of
living organism
• Tissue Level
• Consists of groups of similar cells that have a
common function
• 4 types: epithelium, muscle, connective and nervous
tissues
4. • Organ Level
• Organ is a structure that is composed of at least
two tissue types which performs a specific function
for the body
• System Level
• System is composed of organs that cooperate with
one another to perform a common function
• Organismic Level
• Contains all systems functioning to make a living
being
5.
6.
7. Discovery of Cells
• The invention of the lens
Robert Hooke (1665)
o observed a thin slice of cork (dead
plant cells) with a microscope.
o He described what he observed as
“little boxes” (cells).
9. Cell Theory
• Who developed the cell theory?
• Matthias Schleiden (1838): concluded
that all plants are composed of cells
• Theodor Schwann (1839): concluded
that all animals are composed of cells
• Rudolph Virchow (1855): determined
that cells come only from other cells
10. Cell Theory
• What is the cell theory?
1. All living things are composed of one or more cells
& cell products.
2. Cell is the simplest structural & functional units of
life.
3. Cells come only from preexisting cells, not from
non living matter.
11. Cell…..
N.B
Cells are capable of:
a) Reproducing themselves
b) Synthesizing organelles they need metabolism
c) Eliminating waste materials
d) Regulating movement of materials into & out of
themselves
Some organisms consist of one or a few Cells.
14. Cell Diversity- Shape
• Cells differ widely in shape.
• Most cells are roughly cuboidal or
spherical.
15. Cell Diversity- Internal Organization
Nucleus
o Contains DNA which directs the activity of cell
Organelle
o A cell component that performs specific functions in the cell.
Eukaryotes
o cells that contain a nucleus & membrane-bound organelles.
Prokaryotes
o cells that lack nuclei & membrane-bound organelles.
16. Cells
Parts of a cell
Cell Membrane (or plasma membrane)
Cytoplasm
a) Cytosol
b) Organelles
oMembranous Organelles
oNon-membranous Organelles
c) Inclusions
Nucleus
17. Plasma (Cell) Membrane
oThe outer, limiting barrier
oSeparates internal
contents of cell from
external materials
Functions
1) Selectively permeable
barrier
o Nutrient-in
o Waste-out
2) Communication
3) Intercellular
connections
4) Physical barrier
18. The Nucleus
• Control center of the
cell
• Contains genetic
material (DNA)
• Three regions
• Nuclear membrane
• Nucleolus
• Chromatin
19. Cytoplasm
• Material outside the nucleus and inside the plasma
membrane
• Cytosol
• Fluid that suspends other elements
• Organelles
• Metabolic machinery of the cell
• Inclusions
• Non-functioning units
21. • Endoplasmic reticulum (ER)
• Fluid-filled tubules for carrying substances
• Two types of ER
• Rough Endoplasmic Reticulum
• Studded with ribosomes
• Site where building materials of cellular
membrane are formed
• Smooth Endoplasmic Reticulum
• Functions in cholesterol synthesis and
breakdown, fat metabolism, and
detoxification of drugs
22. • Ribosomes
• Made of protein and RNA
• Sites of protein synthesis
• Found at two locations
• Free in the cytoplasm
• Attached to rough endoplasmic reticulum
• Golgi apparatus
• Modifies and packages proteins
• Produces different types of packages
• Secretory vesicles
• Cell membrane components
• Lysosomes
24. • Lysosomes
• Contain enzymes that digest non-usable
materials within the cell
• Peroxisomes
• Membranous sacs of oxidase enzymes
• Detoxify harmful substances
• Break down free radicals
(highly reactive chemicals)
• Replicate by pinching in half
25. • Mitochondria
• “Powerhouses” of the cell
• Change shape continuously
• Carry out reactions where oxygen is used to break down food
• Provides ATP for cellular energy
26. • Cytoskeleton
• Network of protein structures that
extend throughout the cytoplasm
• Provides the cell with an internal
framework
27. • Cytoskeleton
• Three different types
• Microfilaments
• Intermediate
filaments
• Microtubules
28. • Centrioles
• Rod-shaped bodies made of microtubules
• Direct formation of mitotic spindle during
cell division
29. Cellular Projections
• Not found in all cells
• Used for movement
• Cilia moves materials across the cell
surface
• Flagellum propels the cell
30. Body Tissues
• Cells are specialized for particular
functions
• Tissues
• Groups of cells with similar structure and
function
• Four primary types
• Epithelium
• Connective tissue
• Nervous tissue
• Muscle
31. Epithelial Tissues
• Found in different areas
• Body coverings
• Body linings
• Glandular tissue
• Functions
• Protection
• Absorption
• Filtration
• Secretion
33. • Shape of cells
• Squamous–
flattened
• Cuboidal– cube
shaped
• Columnar – column-
like
34. Connective Tissue
• Found everywhere in the body
• Includes the most abundant and widely
distributed tissues
• Functions
• Binds body tissues together
• Supports the body
• Provides protection
35. Connective Tissue Characteristics
• Variations in blood supply
• Some tissue types are well vascularized
• Some have poor blood supply or are avascular
• Extracellular matrix
• Non-living material that surrounds living cells
36. Connective Tissue Types
• Bone (osseous tissue)
• Composed of:
• Bone cells in
lacunae (cavities)
• Hard matrix of
calcium salts
• Large numbers of
collagen fibers
• Used to protect and
support the body
37. • Hyaline cartilage
• Most common
cartilage
• Composed of:
• Abundant collagen
fibers
• Rubbery matrix
• Entire fetal skeleton
is hyaline cartilage
Cartilage
38. • Elastic cartilage
• Provides elasticity
• Example: supports the external ear
• Fibrocartilage
• Highly compressible
• Example: forms cushion-like discs
between vertebrae
39. • Areolar connective
tissue
• Most widely
distributed
connective tissue
• Soft, pliable tissue
• Contains all fiber
types
• Can soak up excess
fluid
40. • Adipose tissue
• Matrix is an areolar
tissue in which fat
globules predominate
• Many cells contain
large lipid deposits
• Functions
• Insulates the body
• Protects some organs
• Serves as a site of
fuel storage
41. • Blood
• Blood cells
surrounded by fluid
matrix
• Fibers are visible
during clotting
• Functions as the
transport vehicle for
materials
42. Muscle Tissue
• Function is to produce movement
• Three types
• Skeletal muscle
• Cardiac muscle
• Smooth muscle
43. • Skeletal muscle
• Can be controlled
voluntarily
• Cells attach to
connective tissue
• Cells are striated
• Cells have more than
one nucleus
44. • Cardiac muscle
• Found only in the
heart
• Function is to pump
blood (involuntary)
• Cells attached to
other cardiac muscle
cells at intercalated
disks
• Cells are striated
• One nucleus per cell
45. • Smooth muscle
• Involuntary muscle
• Surrounds hollow
organs
• Attached to other
smooth muscle cells
• No visible striations
• One nucleus per cell
46. Nervous Tissue
• Neurons and nerve
support cells
• Function is to send
impulses to other
areas of the body
• Irritability
• Conductivity
47. Regeneration of Tissues
• Tissues that regenerate easily
• Epithelial tissue
• Fibrous connective tissue and bone
• Tissues that regenerate poorly
• Skeletal muscle
• Tissues that are replaced largely with scar
tissue
• Cardiac muscle
• Nervous tissue within the brain and spinal
cord
48. Systems of the body
• The 11 human systems
• Integumentary
• Skeletal
• Muscular
• Nervous
• Endocrine
• Circulatory
• Cardiovascular
• Lymphatic
• Respiratory
• Digestive
• Urinary
• Reproductive
• Immune
49. Integumentary system
• Composed of the skin, sweat
glands, oil glands, hair, and
nails
• Forms the external body
covering
• Protects deep tissues from
injury
• Regulates body temperature
• Site of cutaneous receptors
• Synthesizes vitamin D
• Prevents water loss
50. Skeletal system
• Composed of bones,
cartilages and ligaments
• Provides the framework
for the body
• Protects and supports
body organs
• Site of blood cell
formation
• Stores minerals
• Allows for body movement
51. Muscular system
• Composed of muscles
and tendons
• Produces body movement
• Generates heat
• Maintains posture
52. Nervous system
• Composed of brain and
spinal cord (CNS) and
nerves arising from
them (PNS)
• Control and
coordination
53. Endocrine system
• Composed of endocrine
glands and endocrine
cells that secrete
hormones
• Coordination and
regulation
54. Cardiovascular system
• Composed of the heart
and blood vessels
• The heart pumps blood
• The blood vessels
transport blood
throughout the body in
order to distribute
hormones, nutrients,
gases, and pick up waste
products
55. Lymphatic system
• Composed of thymus, spleen,
lymph nodes, and lymphatic
vessels
• Picks up fluid leaked from
blood vessels and returns it
to blood
• Houses white blood cells
which are involved with
immunity
56. Respiratory system
• Composed of the nasal
cavity, pharynx, larynx,
trachea, bronchi, and
lungs
• Responsible for
exchange of gases
(oxygen and carbon
dioxide) between blood
and the air in the lungs
57. Digestive system
• Composed of Gastrointestinal
tract (GIT) and accessory
organs
• GIT: oral cavity, pharynx,
esophagus, stomach, small
intestine, large intestine
• Accessory organs: teeth,
tongue, salivary glands, liver,
gallbladder & pancreas
• Mechanically and chemically
digests food materials
• Absorbs nutrients
• Expels waste products
58. Urinary system
• Composed of kidneys,
ureters, urinary bladder, and
urethra
• Filters the blood and removes
waste products from the
blood
• Concentrates waste products
in the form of urine, and
expels urine from the body
• Regulates water, electrolyte,
and pH balance of the blood
59. Male Reproductive
system
• Composed of glands,
penis, testes, scrotum,
and ductus deferens
• Produces male sex
cells (sperm) and male
hormones (e.g.,
testosterone)
60. Female Reproductive
system
• Composed of mammary glands,
ovaries, uterine tubes, uterus,
vagina and vulva
• Produces female sex cells
(oocytes) and female hormones
(e.g., estrogen and
progesterone)
• Receives sperm from male
• Site of fertilization
• Site of growth and
development of embryo and
fetus
61. Immune system
• Composed of lymphoid organs (thymus,
spleen, lymph nodes & tonsils) and lymphoid
tissues in other systems
• Defense against disease
