1. Chapter 4-Body organization and Homeostasis

3. Levels of Organization from the simplest to the most complex
Chemical level (atoms, elements, molecules)
Cellular level (made of cells)
Tissue level (groups of cells working together)
Organ level (groups of tissues working together)
Organ System level (groups of organs working together)
Organism

4. Organ Systems In the body

5. Organ Systems In the body

6. 4 Major Tissue Types There are 4 major tissue types in the body:
Epithelial Tissue
Connective Tissue
Muscular Tissue
Nervous Tissue

7. Major Tissue Types
Epithelial tissue covers the body surfaces, cavities and organs.
They also forms glands in the body.
Connective tissue bind structures together; support & protect other tissues. This is the most diverse tissue type and the most widely spread tissue type.
Muscle tissue is responsible for movement.
Nervous tissue carry electrical signals and connect all body parts to the brain and spinal cord.

8. Epithelial Tissue
Epithelial tissues are classified by cell shape and the number of layers of cells
Simple epithelium= one layer of cells
Stratified epithelium= more than one layer of cells
3 cell shapes
Squamous epithelium (flat)
Cuboidal epithelium (cubelike)
Columnar epithelium (Tall)

9. Squamous Epithelial Tissue
Simple squamous
• One layer of flattened cells
• Located in air sacs of lungs & line blood capillaries
• Allows exchange of nutrients, gases, and wastes
Figure 4.1 (1 of 6)

10. Squamous Epithelial Tissue
Stratified Squamous
• Several layers of flattened cells
• Located on surface of skin, lining of mouth, anus,
and vagina
• Provides protection against abrasion, infection,
and drying out
Figure 4.1 (4 of 6)

11. Cuboidal Epithelial Tissue
Simple cuboidal
• One layer of cube-shaped cells
• Located in linings of kidney tubule & duct of pancreas
• Functions in absorption & secretion
Figure 4.1 (2 of 6)

12. Cuboidal Epithelial Tissue
Stratified cuboidal
• Usually two layers of cube-shaped cells
• Located in ducts of mammary glands, sweat glands, & salivary glands
• Functions in protection
Figure 4.1 (5 of 6)

13. Columnar Epithelial Tissue
Simple columnar
• One layer of tall, slender cells
• Located in lining of digestive and respiratory tract
• Functions in absorption & secretion
Figure 4.1 (3 of 6)

14. Columnar Epithelial Tissue
Stratified columnar
• Several layers of tall, slender cells
• Rare, located in urethra (tube that transports urine)
• Functions in protection & secretion
Figure 4.1 (6 of 6)

15. Epithelial Tissue
Table 4.1

16. Cell Junctions
The cells that make up tissues are held together by 3 types of junctions:
Tight junctions
Adhesion junctions (Desmosome)
Gap Junction

17. Tight Junction Proteins interlock in a zipper-like fashion
Plasma
membrane
Intercellular
space
Tight junction
protein
Basement
membrane
Connective
tissue
Tight junction
Proteins interlock in a zipper-like fashion
• prevents the leakage of substances between cells
• Found between epithelial cells of the digestive tract, where they prevent digestive enzymes & microorganisms from entering the blood
Figure 4.5a

18. Adhesion Junction (Desmosome)
Intercellular
space
Adhesion junction (desmosome)
• Intercellular filaments holds cells together despite stretching
• Found in tissues that are often stretched, such as the skin and the opening of the uterus
Figure 4.5b

19. Gap Junction Gap junction
Protein
channels
Intercellular
space
Gap junction
• cells aggregate together creating pores or channels between cells
• Found in epithelia in which the movement of ions coordinates functions, such as the beating of cilia; found in excitable tissue such as heart and smooth muscle
Figure 4.5c

20. Epithelial Cells form Glands
Glands are composed of epithelial cells
2 major types of glands:
Exocrine glands secrete their products into ducts example: sweat glands
Endocrine glands secrete their products directly into blood example: thyroid gland

21. Connective Tissue
Connective tissues contain fewer cells than epithelial tissues
Cells are surrounded by a substance called matrix.
The matrix may contain collagen, elastin, or reticular fibers.

22. Connective Tissue Types of connective tissues Areolar Adipose
Reticular
Dense connective
Cartilage
Bone
Blood

23. Organization of the Human Body
Table 4.2

24. Connective Tissue-Areolar
Areolar connective tissue
• Widely distributed; holds the skin on & and bind organs together
• Wraps and cushions organs
Figure 4.2 (1 of 6)

25. Connective Tissue-Adipose
Adipose (fat) tissue
• Found under skin, around kidneys and heart
• Functions in energy storage and insulation;
cushioning for organs
Figure 4.2 (2 of 6)

26. Connective Tissue-Dense Connective
Dense connective tissue
•Contains fibroblast cells and collagen fibers
Location:
Tendon- connects muscle to bone
ligament- connects bones together
Figure 4.2 (3 of 6)

27. Reticular Tissue Made of reticular cells & reticular fibers
Found in lymph nodes, tonsils etc.

28. Connective Tissue-Cartilage
Cartilage- contains cells called chondrocytes
Lack blood vessels &nerves
healing slower than bone
3 types of cartilage
Hyaline
Elastic
Fibrocartilage

29. Hyaline Cartilage Hyaline cartilage “white cartilage”
Most abundant; provides support & flexibility
The matrix contains tiny collagen fibers that are not visible.
Found in the embryonic skeleton, nose etc.

30. Elastic Cartilage
Matrix contains elastic fibers that help maintain shape
Located in the Auricle of the ear

31. Fibrous Cartilage Matrix contains large collagen fibers
Resistant to stretch
Located in the intervertebral disc between vertebra

32. Bone- most rigid connective tissue
Contains cells called osteocytes
Most rigid connective tissue (hardest)
Protects & supports body parts
Works with muscle to provide movement
Stores calcium & phosphorus
Produces blood cells
Figure 4.2 (5 of 6)

33. Blood Blood – contains a liquid matrix called plasma & formed elements
Plasma – mostly water; also contains nutrients, gases, wastes, salts and hormones.
Formed elements- cells & cell fragments
White blood cells- Help fight infection
Red blood cells- Transport 02 to cells
Platelets- Help with clotting
Figure 4.2 (6 of 6)

34. Muscle Tissue Muscular tissue provides movement; 3 Types: Skeletal
Cardiac
Smooth

35. Skeletal Muscle Tissue
Striation
Nucleus
Width of one
muscle cell
Skeletal muscle
• striated & voluntary
• attached to the skeleton
• responsible for voluntary movement
Figure 4.3 (1 of 3)

36. Cardiac Muscle Tissue Cardiac muscle • striated & involuntary
Striation
Specialized
junction
Nucleus
Cardiac muscle
• striated & involuntary
• branched fibers
• found in wall of heart
Figure 4.3 (2 of 3)

37. Smooth muscle Tissue Smooth muscle • Non-striated & involuntary
Nucleus
Smooth
muscle cell
Smooth muscle
• Non-striated & involuntary
• spindle shaped cells
• found in walls of hollow internal structures such as
the intestines & blood vessels

38. Muscle Tissue
Table 4.3

39. Nervous Tissue Nervous tissue Consists of neurons and neuroglia
Makes up the brain, spinal cord, and nerves

40. Nervous Tissue
neuroglia
Neurons are nerve cells that generate impulses that are conducted to other neurons, muscle cells, or glands
Neuroglia- support cells in nervous tissue

41. Nervous Tissue Parts of a neuron:
Axon
Dendrite
Cell body
Neuron
Neuroglia
Parts of a neuron:
Dendrite- nerve process that brings impulses to the cell body
Cell body- contains the nucleus and cytoplasm
Axon- nerve process that carry electrical signals away from the cell body
Figure 4.4

42. Body Cavities 2 main body cavities in the body: Dorsal cavity
Ventral cavity
Dorsal cavity
Ventral Cavity

43. Dorsal Cavity
Dorsal
cavity
Cranial cavity
contains brain
Spinal cavity
contains
spinal cord
Rib
Ventral
cavity
Thoracic
cavity
Diaphragm
Dorsal cavity- includes the cranial Cavity which houses the brain & The spinal cavity that houses the spinal cord
Abdominal
cavity
Figure 4.7 (2 of 2)

44. Ventral cavity-Thoracic cavity & abdominopelvic cavity
Pleural cavity
Pericardial cavity
The thoracic cavity (chest) contains
the pleural cavities(lungs)
the pericardial cavity (heart)

45. Ventral cavity
Thoracic cavity
Abdominopelvic cavity
The abdominal cavity contains the liver, spleen, kidneys, stomach, pancreas, small intestines & most of the large intestines.
Pelvic cavity contains the last part of the large intestines & the reproductive system

46. Membranes Membranes- made of epithelial & connective tissues
Types of membranes:
Mucous membranes
Serous membranes
Synovial membranes
Cutaneous membrane

47. Membranes
Mucous membranes line tissues that open to the exterior of the body
Serous membranes line the thoracic and abdominal cavities and the organs within them
Synovial membranes line the cavities of joints
Cutaneous membrane forms the skin covering the outside of the body

48. Integument ( skin) – has 3 layers
Hair shaft
Sweat pore
Area of rapidly
dividing cells
Arrector
pili muscle
Sensory
receptor
Epidermis
Oil
(sebaceous)
gland
Dermis
Sensory
nerve fiber
Adipose
tissue
Hypodermis
Sweat gland
Hair follicle
Pressure receptor
Vein
Artery
Hair root
Figure 4.8

49. The Skin Is an Organ System
The Integumentary system is composed of the skin and the structures in it.
Protect the body from invasion by micro-organisms
Prevents water loss
Regulates body temperature
Synthesizes vitamin D
Allow sensations (ex. touch, pressure, pain)
Involved in the removal of waste ( excretion)

50. The Skin Is an Organ System
3 layers
Epidermis – Thin outer layer
Dermis- Thick middle layer that contains most of the structures in the skin
Hypodermis- innermost layer

51. Epidermis Epidermis consists of several layers of epithelial cells
No blood vessels
Deepest layer contains cells undergoing mitosis
Outer surface contains dead keratinized cells
Keratin protects the skin from invasion
Melanocytes in this layer produce melanin that protects the skin from U.V. light.

52. Skin Color Skin color is determined by melanin, carotene & hemoglobin.
Melanin- yellow to brown to black in color
Carotene is a yellowish orange color
Hemoglobin is pink in color
In tanning, the melanocytes respond to the UV radiation by increasing the production of melanin

53. Melanocytes Albino- a person that lacks melanin in the skin.
Vitiligio- the melanocytes disappear from areas of the skin leaving white patches

54. Dermis The dermis – primarily connective tissue Contains blood vessels
Collagen & elastic fibers are found in the lower layer (allow stretching)
Dermal papillae- nipple-like projections that produces the prints on skin (fingerprints)
Stretch marks appear when the tissue tears

55. Sensory Receptors Some sensory receptors in the skin:
Meissner’s corpuscle- touch
Pacinian corpuscle- pressure
Free nerve endings- changes in temperature & pain

56. Hair Dead keratinized cells Primary function is protection
hair shaft extends above the scalp
Hair root located in a hair follicle within dermis

57. Nails and Sebaceous Glands
Nails - dead cells designed to protect the tips of our toes and fingers
Sebaceous (Oil )glands are found all over the body except the palms of the hands and soles of the feet

58. Sweat Glands 2 Types of Sweat Glands:
Eccrine sweat glands- found all over the body; produce sweat that helps regulate body temperature
Apocrine sweat gland- found in the arm pits and groin areas; produce sweat that makes a musky odor.

59. Modified Sweat Glands Modified Sweat glands:
Ceruminous (Wax )glands- found in the external ear canal; produce wax
Mammary gland- found in breast tissue; produce milk.

60. Hypodermis The hypodermis
A layer of loose connective (adipose & areolar) tissue beneath the dermis and epidermis connecting it to other tissues

61. Skin: An Organ System Oil glands Sweat glands Wax glands
Found all over the body except the palms of the hands and soles of the feet
Oil lubricates hair and skin and contains substances that inhibit bacteria
Sweat glands
Produce sweat that helps in the regulation of body temperature
Some metabolic wastes are excreted in sweat
Wax glands
Modified sweat glands found in external ear canal
Wax protects the ear by trapping small particles

62. Homeostasis Homeostasis
The relatively constant internal condition required for life
Depends on the nervous and endocrine systems, which are responsible for internal communication
Maintained primarily through negative feedback mechanisms

63. Homeostasis Negative feedback mechanisms Positive feedback mechanisms
Corrective measures that slow or reverse variation from a normal value
Once the normal value is reached, corrective measures cease
Positive feedback mechanisms
Cause a change that promotes continued change in the same direction

64. Homeostasis Homeostatic mechanisms have three components Receptor
Detects a change in the internal or external environment
Control center (such as the brain)
Integrates the information coming from all receptors and selects an appropriate response
Effector (such as a muscle or gland)
Carries out the response

66. Homeostasis
An example: homeostatic regulation of body temperature by negative feedback mechanisms
In this system
Receptors = thermoreceptors
Control center = hypothalamus (a region of the brain)
Effectors = sweat glands, blood vessels in the skin, and skeletal muscles

68. Homeostasis Hyperthermia Hypothermia
Abnormally elevated body temperature
Can occur if mechanisms for lowering higher-than-normal body temperatures fail
Hypothermia
Abnormally low body temperature
Can occur if body temperature drops too far
Hyperthermia and hypothermia are life-threatening conditions