1. From Cells to Organ Systems4
From Cells to Organ Systems 1

2. Tissues Groups of cells with a common function Four primary tissues
Epithelia
Connective tissues
Muscle
Nervous

3. Epithelial Tissues Two basic purposes
1. Line body cavities and cover surfaces
2. Glandular epithelia
Epithelial cells adapted to make up glands
Exocrine glands
Secrete into ducts to exterior of body
Endocrine glands
Secrete into the blood to carry chemical messages throughout the body

4. Epithelial Tissues: Classification
Shape
Squamous
Flattened cells
Line vessels, part of lungs, body surface
Cuboidal
Cube shaped
Form lining of tubules, glandular tissue
Columnar
Column shaped
Line respiratory, digestive, reproductive tracts

5. Epithelial Tissues: Classification
Number of layers
Simple/single-layered
Adapted for diffusion across cell barriers
Line glands, and respiratory, digestive, reproductive systems
Stratified/multiple-layered
Provide protection, as in the skin surface

6. Most epithelial tissues line or cover surfaces or body cavities.
Figure 4.1
Simple squamous
Lines blood vessels and air sacs
of lungs
Permits exchange of nutrients, wastes, and gases
Stratified squamous
Outer layer of skin, mouth, vagina
Protects against abrasion, drying out, infection
Stratified cuboidal
Lines ducts of sweat glands
Secretes water and ions
Simple cuboidal
Lines kidney tubules and glands
Secretes and reabsorbs water and small molecules
Stratified columnar
Lines epididymus, mammary glands, larynx
Secretes mucus
Simple columnar
Lines most digestive organs
Absorbs nutrients, produces mucus
Figure 4.1 Types of epithelial tissues.
Goblet cell
Basement membrane
Most epithelial tissues line or cover surfaces or body cavities.
Exocrine gland
Endocrine gland
Gland cells
Gland cells
Blood flow
Glandular epithelia secrete a product. 6

7. The Basement Membrane Provides Structural Support
Noncellular layer directly beneath epithelial tissue
Composed of proteins secreted by epithelial cells and connective tissue
Provides structural support to overlying cells
Attaches epithelial layer to underlying tissues

8. Cell Junctions—Hold Adjacent Cells Together
Tight junctions
Seal plasma membranes tightly together
Digestive tract lining, bladder lining
Adhesion junctions/spot desmosomes
Permit some movement between cells
Allow tissues to stretch and bend
Skin
Gap junctions
Protein channels enable movement of materials between cells
Liver, heart

9. flexibility of movement. Gap junctions provide for the direct transfer
Figure 4.2
Tight junction
proteins
Protein
filaments
Protein
channel
Figure 4.2 Examples of junctions between cells.
Intercellular
space
Intercellular
space
Intercellular
space
Tight junctions form
leak-proof seals
between cells.
Adhesion junctions
anchor two cells
together, yet allow
flexibility of movement.
Gap junctions provide
for the direct transfer
of water and ions
between adjacent
cells. 9

10. Connective Tissue General functions
Supports softer organs of body
Connects parts of body
Stores fat
Produces blood cells
Contains cells embedded in nonliving extracellular matrix
Matrix provides the strength
Two general types
Fibrous and special

11. Fibrous Connective Tissue
Function: provides strength and elasticity
Contains fibers and cells embedded in gel-like ground substance (matrix)
Matrix: intercellular material giving the CT its characteristics
Cells: fibroblasts, macrophages, lymphocytes, and neutrophils
Fibers: collagen, elastic, and reticular

12. Fibrous Connective Tissue
Four general types
Loose: surrounds many organs, lines cavities around blood vessels
Dense: forms tendons, ligaments, deeper layers of skin
Elastic: surrounds stomach and bladder, maintains shape
Reticular: makes up internal framework of soft organs (liver) and the lymphatic system

13. Mast cell Fibroblast Elastic fiber Reticular fiber Macrophage
Figure 4.3
Mast cell
Fibroblast
Elastic
fiber
Reticular fiber
Macrophage
Nerve fiber
Lymphocyte
Collagen fiber
Figure 4.3 Fibrous connective tissue.
Neutrophil
Plasma cell
Ground
substance
Fat cell
Capillary 13

14. Loose areolar connective tissue ( 160). In loose connective
Figure 4.4
Elastin fibers
Fibroblast
Collagen
fibers
Loose areolar connective tissue ( 160). In loose connective
tissue the collagen and elastin fibers are arrayed in a random pattern.
Collagen
fibers
Figure 4.4 Examples of fibrous connective tissues.
Nuclei of
fibroblasts
Dense connective tissue ( 160). In dense connective
tissue the fibers are primarily collagen fibers. In tendons and
ligaments the fibers are oriented all in the same direction,
with fibroblasts occupying narrow spaces between adjacent fibers. 14

15. Specialized Connective Tissues Serve Special Functions
Cartilage: produced by chondroblasts found in lacunae; no blood vessels; high collagen content
Bone: inorganic matrix with calcium salts for hardness
Blood: fluid matrix of plasma, red blood cells, white blood cells, and platelets
Adipose tissue: fat cells; function in insulation, protection, and energy storage

16. Adipose tissue from the subcutaneous layer under the skin ( 140).
Figure 4.5
Chondrocyte
in lacuna
Ground
substance
Cartilage from the trachea ( 300). Mature cartilage cells, called chondrocytes,
become trapped in chambers called lacunae within the hard, rubbery ground substance.
Ground substance is composed of collagen fibers, polysaccharides, proteins, and water.
Vacuole
containing
stored fat
Figure 4.5 Examples of special connective tissues.
Blood
vessel
Nuclei of
fat cells
Adipose tissue from the subcutaneous layer under the skin ( 140).
Adipose tissue consists almost entirely of fat cells. The fat deposit within a
fat cell can become so large that the nucleus is pushed to the side. 16

17. Muscle Tissue Contracts to Produce Movement
Skeletal muscle
Moves body parts
Voluntary, multinucleated
Cardiac muscle
Functions in the heart
Involuntary, single nucleus
Smooth muscle
Surrounds hollow structures

18. Skeletal muscle ( 100). Skeletal muscle cells
Figure 4.6
Nuclei
Intercalated
disc
Width
of one
muscle
cell
Nucleus
Skeletal muscle ( 100). Skeletal muscle cells
are very long and have many nuclei.
Cardiac muscle ( 225). Cardiac muscle cells
Interconnect with each other.
Smooth
muscle
cell
Figure 4.6 Muscle tissue.
Nucleus
Sheet of smooth muscle ( 250). Smooth muscle
cells are thin and tapered. 18

19. Nervous Tissues Transmit Impulses
Neuron: specialized nervous system cell
Function: generate and transmit electrical impulses
Structural components: cell body, dendrites, axon
Glial cells
Function:
Surround and protect neurons
Provide nutrients to neurons

20. Axon Nuclei of glial cells Cell body Dendrites Figure 4.7
Figure 4.7 Nervous tissue: a neuron.
Dendrites 20

21. Organs and Organ Systems Perform Complex Functions
Contain two or more tissue types joined together; perform specific functions
Organ systems
Groups of organs that perform a common function
Examples
Digestive system: mouth, throat, stomach, intestines, and liver
Lymphatic system: lymph nodes, tonsils, and spleen

22. Body Cavities Anterior cavity Posterior cavity
Thoracic cavity
Two pleural cavities
Pericardial cavity
Abdominal cavity
Posterior cavity
Cranial cavity
Spinal cavity
Tissue membranes (serous membranes) line body cavities

23. Cranial cavity Posterior cavity Vertebral canal Pericardial cavity
Figure 4.8
Cranial
cavity
Posterior
cavity
Vertebral
canal
Pericardial
cavity
Thoracic
cavity
Pleural
cavity
Diaphram
separates
thoracic and
abdominal
cavities
Anterior
cavity
Abdominal
cavity
Figure 4.8 The main body cavities.
Pelvic
cavity 23

24. Tissue Membranes Serous membranes: Mucous membranes:
Line and lubricate internal body cavities
Reduce friction between organs
Mucous membranes:
Lines airways, digestive tract, reproductive tract
Lubricate surface, captures debris
Synovial membranes:
Line spaces in movable joints
Cutaneous membranes:
Outer covering (skin)

25. Describing Body Position or Direction
Three body planes
Midsagittal
Divides body into left and right sides
Frontal
Divides body into front and back
Transverse
Divides body into top and bottom

26. Describing Body Position or Direction
Terms to describe relative position
Anterior: at or near the front
Posterior: at or near the back
Proximal: nearer to the body trunk
Distal: farther away from the body trunk
Superior: situated above or directed upward
Inferior: situated below or directed downward

27. Superior Distal Proximal Inferior Posterior Anterior (closer to
Figure 4.9
Superior
(closer to
the head or
upper part of
a structure)
Frontal
plane
Distal
(farther away
from the trunk)
Transverse
plane
Proximal
(nearer to
the trunk)
Figure 4.9 Planes of symmetry and terms used to describe position or direction in the human body.
Inferior
(farther from
the head or
toward the
lower part of
a structure)
Posterior
(at or near
the back)
Anterior
(at or near
the front)
Midsagittal
plane 27

28. The Skin As an Organ System
The proper name is integumentary system
Includes skin, hair, nails, glands
Functions
Protection from dehydration
Protects from injury
Serves as defense against microorganisms
Regulates body temperature
Makes vitamin D
Provides sensation

29. Epidermis Dermis Hypodermis Free nerve endings Hair follicle
Figure 4.10
Free nerve
endings
Hair follicle
Hair shaft
Hair root
Small blood
vessels
Epidermis
Sebaceous
gland
Dermis
Vein
Artery
Smooth
muscle
Figure 4.10 The skin.
Adipose
tissue
Hypodermis
Sweat gland
Nerve
Receptors 29

30. Skin Consists of Epidermis and Dermis
Outer layer
Stratified squamous epithelial cells
No blood vessels
Two major cell types
Keratinocytes: provide a tough waterproof protein (keratin)
Melanocytes: provide dark pigment (melanin)

31. Melanocyte containing melanin granules
Figure 4.11
Dead
cells of
epidermis
Keratinocyte
containing melanin
Living cells
of epidermis
Melanocyte containing
melanin granules
Dividing keratinocyte
(basal cell)
Figure 4.11 The epidermis.
Basement membrane
Blood vessel
Dermis with
blood vessel 31

32. Skin Consists of Epidermis and Dermis
Lies underneath the epidermis
Supports tissues
Fibers
Collagen
Elastic
Cells
Fibroblasts (most abundant)
Mast cells
White blood cells
Fat cells

33. Accessory Structures of Dermis
Hair
Shaft
Follicle
Smooth muscle
Attached to hair follicle, raises hair to upright position
Oil glands/sebaceous glands
Secretion moistens and softens skin
Sweat glands
Blood vessels
Sensory nerve endings

34. Accessory Structures of Dermis
Sweat glands
Secrete sweat, help in temperature regulation
Sebaceous glands
Secrete oil to moisten and soften hair and skin
Blood vessels
Supply nutrients, remove waste, assist in temperature regulation
Sensory nerve endings
Detect heat, cold, touch, deep pressure, vibration

35. Negative Feedback Helps Maintain Core Body Temperature
Controlled variable: body temperature
Sensors: temperature sensors in skin and internal organs
Control center: hypothalamus
Effectors
Blood vessels
Sweat glands
Skeletal muscles