The document discusses the different levels of organization in the human body from molecules to cells to tissues to organs to organ systems. It focuses on the four main types of tissues - connective, muscular, nervous, and epithelial tissues. Connective tissue is further divided into fibrous, supportive, and fluid connective tissues. The major components and functions of each type of tissue are described.

1. Human Organization
Module 2 Chapter 4

2. Levels of Organization
molecules → cells→ tissues →
organs → organ system

3. Tissue
 A collection of cells of the same type
that perform a common function
 There are 4 major tissue types in the
body:
1. Connective
2. Muscular
3. Nervous
4. Epithelial

4. Connective Tissue
 Binds and supports parts of the body
 All have specialized cells, ground
substance and protein fibers
 There are three main types of connective
tissue: A. fibrous , B. supportive and C.
fluid

5. Connective Tissue

6. Ground Substance
 Ground substance is noncellular and
ranges from solid to fluid
 The ground substance and protein fibers
together make up the matrix of the tissue

7. Fibres
 Collagen: white, gives flexibility and
strength
 Reticular: thin collagen, branched,
support network
 Elastic: yellow, elastin, very flexible
protein, not as strong as collagen

9. Specialized Connective
Tissue Cells
 Blood cells
 Mast cells
 Stem cells
 Adipose cells
 Fibroblasts

10. Fibrous Connective Tissue
 There are two types: dense or loose, but
both contain fibroblast cells with a matrix
of collagen and elastic fibers
 Loose fibrous tissue is found supporting
epithelium and many internal organs
 Adipose tissue is a special loose fibrous
tissue where fat is stored

11. Fibrous Connective Tissue
Loose Fibrous (areolar tissue) Dense Fibrous
1. Supports epithelium and internal organs Many tightly packed collagen fibres
2.Allows for expansion of organs ie
bladder, lungs
Tendons (connect muscle to bone)
3.Protective covering for
internal organs ie muscle, nerves,
blood vessels
Ligaments (connects bone to other bones
at joints)
Adipose tissue special type,
enlarged cells to store fat
Fat used for energy, insulation and
protection under skin, around organs
and on surface of heart
Matrix for both has collagen and elastin fibres
Ground substance is gel-like

12. Fibrous Connective Tissue

13. Supportive Connective
Tissue
 Cartilage:
 Cells are in chambers called lacunae
 Ground substance (matrix) is solid but
flexible
 No direct blood supply
 3 types are distinguished by types of fibers

14. Types of Cartilage
 Hyaline cartilage – most common type,
fine collagen fibers
 Location: Nose, ends of long bones and fetal
skeleton
 Elastic cartilage – more elastic fibers than
cartilage fibers, more flexible
 Location: Outer ear, epiglottis
 Fibrocartilage – strong collagen fibers,
withstand tension and pressure
 Location: Disks between vertebrae, knee

15. Supportive Connective
Tissue
 Bone:
 Cells are in chambers called lacunae
 Matrix is solid and rigid that is made of
collagen and calcium salts
 Most rigid connective tissue
 Has nerve cells and blood supply
 2 types are distinguished by types of fibers

16. Types of Bone
 Compact: Location: Shafts of long bone
 Spongy: Location: Ends of long bones
 Composition of bone will be studied in more depth
with Skeletal System

17. Fluid Connective Tissue
 Blood:
 Often not considered connective tissue, but
vascular tissue
 Made of a fluid matrix called plasma and
cellular components that are called formed
elements
 Formed elements: red and white blood cells
and platelets

18. Blood: Formed Elements
 3 formed elements:
 Red blood cells:
cells that carry
oxygen
 White blood cells:
cells that fight
infection
 Platelets: pieces of
cells that clot blood

19. Fluid Connective Tissue
 Lymph:
 Clear, watery, yellowish fluid (lymph) made by
lymphatic tissue
 White blood cells congregate in this tissue
 Absorb excess tissue fluids and transport
dissolved solutes and fat molecules
 Lymph nodes clean lymph
 Help fight infection

20. Muscle Tissue
 Allows for movement in the body
 Made of muscle fibers/cells and protein
fibers called actin and myosin
 There are 3 types of muscle tissue in
humans:
 A. Skeletal
 B. Smooth
 C. Cardiac

21. Muscle Tissue: Skeletal
 Appearance: long,
cylindrical cells, multiple
nuclei, striated fibers (light
and dark bands of actin
and myosin)
 Location: attached to
bone for movement
 Nature: voluntary
movement

22. Muscle Tissue: Smooth
 Appearance: spindle-
shaped cell with one
nucleus, lack striations
 Location: walls of hollow
organs (eg. Intestine,
bladder, etc) and blood
vessels
 Nature: involuntary
movement

23. Muscle Tissue: Cardiac
 Appearance: branched
cells with a single nucleus,
striated
 Location: heart
 Nature: involuntary
movement

24. Nervous Tissue
 Allows for communication between cells
through sensory input, integration of data
and motor output
 Made of 2 major cell types:
A. Neurons
B. Neuroglia

25. Neurons
 Made of dendrites, a
cell body and an axon
 Dendrites carry
information toward the
cell body
 Axons carry information
towards a cell body

26. Neuroglia
 A collection of cells that
support and nourish
neurons
 Outnumber neurons 9:1
 Examples are
oligodendrocytes,
astrocytes and microglia

27. Epithelial Tissue
 A groups of cells that form a tight, continuous
network – have a basement membrane
 Lines body cavities, covers body surfaces and found
in glands
 protective covering, secretion, absorption, excretion,
filtration
 Types: simple, stratified
 Basement Membrane:
 Thin layer of carbohydrates and proteins used to anchor epithelial
tissue to underlying connective tissue

28. Simple Epithelia
 Number of cell layers:
 Simple: one layer of cells
 Stratified: more than one layer of cells
 Pseudostratified: appears to have layers but
only has one layer
 Shape of cell:
 Cuboidal: cube-shaped
 Columnar: column-shaped
 Squamous: flattened

31. Glands
 epithelial tissue that secrete substances are
termed glandular epithelial.
 may be single cells (sweat and mucous glands)
or multiple (endocrine glands eg.pancreas)

32. Cell Junctions
 Epithelial cells cover the surface of
organs and line body cavities.
 Depending on their location, their
function at that site dictates the manner
in which they are connected to each
other and to nerves and muscles.

33. Cell Junctions
 If the epithelial layer must be impermeable,
proteins will join each cell forming a tight
junction. This occurs in stomach, intestines
and kidneys.
 Tissue that is exposed to mechanical stress is
joined by adhesion junctions. Proteins
again join the epithelial cell, but allow some
stretching of the cells by creating a small
space between the cell membranes. These
junctions are found in skin.

34. Cell Junctions
 If some communication must occur
throughout a tissue, the junction must
allow for some ions and molecules to
pass from one cell to another.
 The gap junction makes up part of the
cardiac muscle, allowing electrical
impulses to coordinate one heart beat.

35. Cell Junctions

36. The integumentary system
 Includes the skin and accessory organs such as
hair, nails and glands
 The skin has two main regions called the
epidermis and the dermis
 Under the skin there is a subcutaneous layer
between the dermis and internal structures
where fat is stored
 Is important for maintaining homeostasis

37. Function
1. Protects the body from physical trauma,
invasion by pathogens and water loss
2. Helps regulate body temperature
3. Allows us to be aware of our surroundings
through sensory receptors
4. Synthesizes chemicals such as melanin
and vitamin D

38. Skin Layers

39. Epidermis
 The thin, outermost layer of the skin
 Made of epithelial tissue
 Cells in the uppermost cells are dead
and become filled with keratin thus
acting as a waterproof barrier

40. Epidermis continued
 new cells constantly being produced at
innermost layer by stem cells
 Langerhans cells are a type of white blood
cell that help fight pathogens
 Melanocytes produce melanin that lend to
skin color and protection for UV light
 Some cells convert cholesterol to vitamin D

42. Dermis
 The thick, inner layer of the skin
 Made of dense fibrous connective tissue
 Contains elastic and collagen fibers
 Contains blood vessels, many sensory
receptors and glands

43. Dermis
 sebaceous (oil) glands secrete sebum.
The oil moves to epidermis layer to act
as protectant, lubricant and waterproof
 sweat glands for body temperature
control and also anti-bacterial

44. Subcutaneous Layer
 Located below the dermis, this layer is
the site of “subcutaneous” injections. It is
made up of adipose and loose
connective tissue.
 The subcutaneous layer is NOT part of
the skin. Its function is protection and an
energy source.

45. Accessory Organs
 originate in the epidermal layer
 Includes nails, hair and glands
 Nails
 nail roots begin in epithelial layer
 cuticle protects root
 lunula (half-moon) is thick cell layer
 nail made up of keratin (protein)

46. Accessory Organs
 Hair
 follicles start as bulb in dermis and grow to
outside epidermis
 colour dictated by melanin (and iron and
sulfur content in the pigment)
 muscles cause hair to become erect
 Sweat Glands
 present in all regions of skin
 begins in dermis
 opens to epidermis or hair follicle
 help to control body temperature

48. Moving from tissue to
organs and organ systems
 An organ is 2 or more tissue types
working towards a particular function
 An organ system is a combination of
organs that work together to carry out a
particular function

51. Body Cavities

52. Membranes
 Mucous membranes – lining of the digestive, respiratory,
urinary and reproductive systems
 Serous membranes – line lungs, heart, abdominal cavity
and cover the internal organs; named after their location
• Pleura: lungs
• Peritoneum: abdominal cavity and organs
• Pericardium: heart
 Synovial membrane – lines the cavities of freely movable
joints
 Meninges – cover the brain and spinal cord

53. Homeostasis
Maintaining relative constancy within an environment.
 Warm blooded animals maintain a constant internal
environment by communication between organ systems
 If constancy is not maintained, illness results
 The endocrine and nervous system play a major role in
maintaining homeostasis
 Regulation is monitored and controlled by feedback
mechanisms

54. Negative Feedback
 The primary mechanism
for maintaining
homeostasis
 Has two components:
• sensor
• control center
 The output of the system
dampens the original
stimulus

55. Negative
Feedback
 Eg. maintaining body
temperature

56. Positive Feedback
 A mechanism for increasing the change
of the internal environment in one
direction
 An example is the secretion of oxytocin
during birth to continually increase
uterine contractions
 Can be harmful such as when a fever is
too high and continues to rise

57.  Explain how the following are
examples of negative feedback:
body temperature regulation
glucose regulation

58.  Explain how the following are
examples of positive feedback:
nursing
childbirth