A&p Lecture 5-6:

Front 1

Tissues

Back 1

A collection of specialized cells and cell products that perform a specific, LIMITED function
-- having a limited function doesn't mean that cells can't
survive on their own (still have their own organelles,
etc.)


- Structures with discrete structural and functional
properties
- Tissues combine to form organs (Ex: heart or liver)

Front 2

How many organ systems are there?

Back 2

Organs can be grouped into 11 organ systems.

Front 3

Basic Types of Tissues

Back 3

1. Epithelial Tissue
2. Connective Tissue
3. Muscle Tissue
4. Neural Tissue

Front 4

Epithelial Tissue

Back 4

Cells that cover body or inner lining of body to protect it

- Covers exposed surfaces (Ex: Skin)
- Lines internal passageways (Ex: Digestive Tract)
- Forms Glands (Ex: Sweat Glands, Endocrine Glands)

Front 5

Connective Tissue

Back 5

*composed of many types of cells

- Fills internal spaces (Ex: Adipose)
- Supports other tissues (Ex: Bone)
- Transports materials (wastes, nutrients, etc.) (Ex: Blood)
- Stores energy reserves (Ex: Adipose)

Front 6

Muscle Tissue

Back 6

- specialized for contraction
- Three Different Types

Front 7

Types of Muscle Tissue:

Back 7

1. Skeletal Muscle (the only muscle type with voluntary
control)

2. Cardiac (heart) Muscle

3. Smooth Muscle (walls of hollow organs)

Front 8

Neural Tissue

Back 8

Function:
-- Carries electrical signals from one part of the body to
another (either from body to brain or brain to body)

*Includes neurons and neuroglia that support them

Front 9

Epithelia

Back 9

Layers of cells covering internal or external surfaces

Front 10

Internal Surfaces

Back 10

Lines digestive, respiratory, reproductive, and urinary tracts

Front 11

External Surfaces

Back 11

Surface of skin

Front 12

Glands

Back 12

Structures that produce secretions

Two Types:
1. Exocrine Glands
2. Endocrine Glands

Front 13

Exocrine Glands

Back 13

release substances onto a surface

Ex: Release sweat onto skin; digestively release enzymes into stomach

Front 14

Endocrine Glands

Back 14

Release substances into interstitial fluid surrounding it

Ex: through capillaries

Front 15

Functions of Epithelial Tissue:

Back 15

1. Provide Physical Protection

2. Control Permeability

3. Provide Sensation

4. Produce Specialized Secretions
- glandular epithelium

Front 16

Control Permeability

Back 16

** A function of Epithelial Tissue

can be regulated and modified in response to stimuli

Ex: Hormones can affect transport across epithelia, physical labor forms calluses

Front 17

Provide Sensation

Back 17

** A function of Epithelial Tissue

- Contains sensory neurons
- Neuroepithelium

Front 18

Neuroepithelium

Back 18

Epithelium specialized to perform a specific sensory function (smell, taste, sight, hearing, equilibrium)

Front 19

Produce Specialized Secretions

Back 19

** A function of Epithelial Tissue

Glandular Epithelium

Front 20

5 Qualities of Epithelia:

Back 20

1. Polarity

2. Cellularity

3. Attachment

4. Avascularity

5. Regeneration

Front 21

Polarity

Back 21

**A quality of epithelia

Apical (top) and basal (bottom) surfaces

Front 22

Apical

Back 22

top

surface where the cell is exposed to an internal or external environment

Contains:
1. Microvilli
2. Cilia

Front 23

Microvilli

Back 23

increase absorption or secretion

Ex: Digestive and Urinary tracts

Front 24

Cilia

Back 24

Ciliated Epithelium

move fluid

Ex: Respiratory tract

Front 25

Basal (basolateral)

Back 25

bottom

Includes BOTH the base and the sides of the cell that comes into contact with its neighbors

Front 26

Cellularity (intercellular connections)

Back 26

**A quality of epithelia

* Support and communication

Epithelia are interconnected by cell junctions

Each of the cells are connected to each other by trans-membrane proteins
-- Provides support, strength and communication to the cell

Front 27

Attachment

Back 27

**A quality of epithelia

Base of epithelia are attached to basement membrane, or basal lamina

Front 28

Avascularity

Back 28

**A quality of epithelia

lack blood vessels

Front 29

Regeneration

Back 29

**A quality of epithelia

Continuously replaced by stem cell divisions

(Since epithelial cells are always exposed to external environment, they are in constantly changing environments and die a lot. That is why epithelial cells can regenerate)

Front 30

Intercellular Connections (Cellularity)

Back 30

**A quality of epithelia

Support and Communication
1. CAM's (cell adhesion molecules)
2. Cell Junctions

Front 31

CAMs

Back 31

Cell Adhesion Molecules

Trans-membrane proteins that bind to large areas of the plasma membrane to other cells or to extracellular materials

Front 32

Cell Junctions

Back 32

specialized areas of membrane that form bonds with other cells or extracellular material

3 Types (tight junctions, gap junctions, desmosomes)

Front 33

Types of Cell Junctions:

Back 33

1. Tight Junctions

2. Gap Junctions

3. Desmosomes

Front 34

Tight Junctions:

Back 34

Interlocking membrane proteins connect plasma membrane

- Very Tight Seal
-- Prevents passage of water and solutes between the
connected membranes
- In the lumen (passageway) of the digestive tract, function
to isolate enzymes, acids, and wastes
-- Keeps those items inside the lumen

Front 35

Gap Junctions

Back 35

Holds two cells together by channel proteins (junctional proteins, connexons)
-- Allow rapid communication
--- Allows movement of small molecules and ions
between cells
-- Coordinate contractions in heart muscle

* Not only do they connect cells together, but they have a hole of some sorts that allows cytoplasm from one cell to be connected to another (Allows for movement of materials between cells quickly)

Front 36

Desmosomes

Back 36

very strong, can resist stretching, bending, twisting, compression

CAMs connect adjacent plasma membranes

Two Types of Desmosomes (Spot and Hemidesmomsomes)

Front 37

Two Types of Desmosomes:

Back 37

1. Spot desmosomes

2. Hemidesmosomes

Front 38

Spot Desmosomes

Back 38

small discs connected to intermediate filaments, ties cell together, stabilizes cel

Front 39

Hemidesmosomes

Back 39

"half of a spot desmosome"

attach cells to the basal lamina to anchor underlying tissue

Front 40

Attachment (to the Basement Membrane)

Back 40

**A quality of epithelia

Two Layers:
1. Clear Layer (lamina lucida)
2. Dense Layer (lamina densa)

Front 41

Clear Layer

Back 41

lamina lucida

layer closest to epithelia
-- Thin layer secreted by epithelia
-- Functions as barrier to proteins

Front 42

Dense Layer

Back 42

lamina densa

- Thick fibers produced by connective tissue
- Provides strength and acts as a filter for diffusion of
materials between adjacent tissue and epithelium

Front 43

Avascularity

Back 43

**A quality of epithelia

no blood vessels in epithelial tissue

Nutrients, gases, wastes need to diffuse to/from tissue

Front 44

Regeneration

Back 44

*Epithelial Maintenance and Repair

Epithelia are replaced by division of germinative cells (stem cells)
-- Near basement membrane

Front 45

Germinative Cells

Back 45

stem cells

Front 46

Singular form

Back 46

Epithelium

Front 47

Plural form

Back 47

Epithelia

Front 48

Classes of Epithelia

Back 48

1. Based on Shape
2. Based on Layers

Front 49

Based on Shape

Back 49

*a way to classify epithelia

1. Squamous epithelia (thin and flat)

2. Cuboidal epithelia (square shaped)

3. Columnar epithelia (tall, slender rectangles)

Front 50

Based on Layers

Back 50

*a way to classify epithelia

1. Simple epithelium (single layer of cells)

2. Stratified epithelium (several layers of cells)

Front 51

"Special" Simple Squamous Epithelia

Back 51

single layer of flat and thin epithelial cells

- Lones chambers and passageways that do not
communicate with outside world
- Includes:
1. Mesothelium
2. Endothelium

Front 52

Mesothelium

Back 52

lines body cavities

Ex: Pleura, peritoneum, pericardium

Front 53

peritoneum

Back 53

mesothelium that surrounds abdominal cavity and lines its organs

Front 54

pericardium

Back 54

mesothelium that surrounds the heart

Front 55

Endothelium

Back 55

lines inner surface of heart and blood vessels

Front 56

Gladular Epithelia

Back 56

*remember, glands are composed of epithelial cells

Two Types:
1. Endocrine Glands
2. Exocrine Glands

Front 57

Endocrine Glands:

Back 57

ductless glands

- Release hormones into interstitial fluid which then enters
the bloodstream (not secreted onto a surface)

Ex: Thyroid, pituitary (anterior and posterior) glands

Front 58

Exocrine Glands

Back 58

glands with ducts

- Produce secretions that are released onto epithelial
surfaces
- Classified by mode and type of secretion
-- Three Modes
-- Three Types

Ex: Sweat from sweat glands, milk from mammary glands

Front 59

Modes of Secretion by Exocrine Glands

Back 59

1. Merocrine Secretion

2. Apocrine Secretion

3. Holocrine Secretion

Front 60

Merocrine Secretion

Back 60

*exocrine glands

* Most common mode of secretion

- Released by vesicles (exocytosis)

Ex: sweat glands, mucin (mixes with water to form mucus)

Front 61

Apocrine Secretion

Back 61

*exocrine glands

Release of substances through shedding of the apical surface

- Released by shedding cytoplasm
- Apical part of cell is lost (along with the cytoplasm and
inclusions

Front 62

Holocrine Secretion

Back 62

*exocrine glands

Cells fill up with materials it wants to secrete and then bursts

- Released by cells bursting, killing gland cell
-- Entire cell fills with secretory products before bursting
- Gland cells replaced by stem cells

Ex: sebaceous glands found at hair follicles

* These cells actually die and need to be replenished (hence the stem cells)

Front 63

Mode that Mammary Glands Secrete Milk

Back 63

Release milk by combination of apocrine and merocrine secretions

Front 64

Types of Exocrine Secretions:

Back 64

1. Serous Glands

2. Mucous Glands

3. Mixed Exocrine Glands

Front 65

Serous Glands

Back 65

watery secretions

Ex: saliva by parotid salivary glands

Front 66

Mucous Glands

Back 66

Secrete mucins (mixes with water to form mucus)

Ex: Mucins from sublingual salivary glands and submucosal glands of small intestine

Front 67

Mixed Endocrine Glands

Back 67

both serous and mucous

Ex: Submandibular (salivary) glands

Front 68

Two Main Exocrine Groups

Back 68

1. Unicellular Glands

2. Multicellular Glands

Front 69

Unicellular Glands

Back 69

*exocrine glands

Mucous (goblet) cells are the ONLY unicellular exocrine glands (most common type)
-- Scattered among epithelia

Ex: in intestinal lining (secretes mucous onto lining)

Front 70

Multicellular glands

Back 70

*Exocrine glands

Secretory sheet where gland cells can form epithelium that releases product into an inner compartment

Ex: Mucin-secreting cells in stomach, salivary glands

Front 71

Characteristics to Describe Multicellular Exocrine Glands:

Back 71

1. Structure of the Duct

2. Shape of Secretory Portion of the Gland

3. Relationship Between Ducts and Glandular Areas

Front 72

Structure of the Duct

Back 72

*A Characteristic to Describe Multicellular Exocrine Glands

1. Simple (undivided) - Single duct

2. Compound (divided) - divides one or more times on its
way to the gland cells

Front 73

Shape of Secretory Portion of the Gland:

Back 73

*A Characteristic to Describe Multicellular Exocrine Glands

1. Tubular:
-- Tube shaped
-- can be straight or coiled

2. Alveolar or acinar
-- blind pockets

3. Tubuloalveolar or tubuloacinar
-- Both tubes AND pockets

Front 74

Tubular

Back 74

tube shaped

Front 75

Alveolar (acinar)

Back 75

blind pockets

Front 76

Tubuloalveolar (tubuloavinar)

Back 76

both tubes AND pockets

Front 77

Relationship Between Ducts and Glandular Areas

Back 77

*A Characteristic to Describe Multicellular Exocrine Glands

Branched:
-- Several secretory areas sharing one duct

Front 78

Basic Characteristics of Connective Tissue

Back 78

1. Specialized Cells (more than 1 cell type)

2. Solid Extracellular Protein Fiber (for support)

3. Fluid Extracellular Ground Substance

Front 79

Ground Substance

Back 79

besides filling the spaces between cells, the ground substance also slows pathogen movement

Front 80

Matrix

Back 80

the extracellular components of connective tissue
-- Fibers and Ground Substance

- The majority of connective tissue volume
- Determines specialized function

Front 81

Functions of Connective Tissue

Back 81

1. Establishing a structural framework for the body

2. Transporting fluids and dissolved materials (Ex: lymph)

3. Protecting Delicate Organs (Ex: Adipose tissue)

4. Supporting, Surrounding, and Interconnecting other
types of tissue (Ex: Regular and Irregular Disconnective
Tissue)

5. Storing Energy Reserves (especially in the form of
triglycerides)

6. Defending the body from invading microorganisms (Ex:
WBC's)

Front 82

Three Categories of Connective Tissue:

Back 82

1. Connective Tissue Proper

2. Fluid Connective Tissues

3. Supporting Connective Tissues

Front 83

Connective Tissue Proper

Back 83

*A category of connective tissue

Functions to connect and protect

More rigid and used to bind things together

Ex: Tendons and adipose

Front 84

Fluid Connective Tissues

Back 84

*A category of connective tissue

Function in transportation

Ex: Blood and Lymph
-- Transport materials to cells and wastes away from
cell

Front 85

Supporting Connective Tissues

Back 85

*A category of connective tissue

Provides structural strength

Ex: Cartilage and Bone

Front 86

Connective Tissue Proper Cell Populations:

Back 86

1. Fibroblasts
2. Fibrocytes
3. Adipocytes
4. Mesenchymal Cells
5. Macrophages
6. Mast Cells
7. Lymphocytes
8. Melanocytes

Front 87

Fibroblasts

Back 87

The most abundant cell type

found in all connective tissue proper

secrete proteins and hyaluronan (cellular cement)

Front 88

Hyaluronan

Back 88

cellular cement secreted by fibroblasts

holds things together and prevents cells from moving around too much

Front 89

Fibrocytes

Back 89

the second most abundant cell type
-- Develop from Fibroblasts!!!!

Found in all connective tissue proper
Maintain the fibers of connective tissue proper

Front 90

Adipocytes

Back 90

Adipose Cells (Fat cells)

Each cell stores a single, large fat droplet
(droplet grows/shrinks)

Functions as energy reserve and cushions tissues/organs

Front 91

Mesenchymal Cells

Back 91

Found in many connective tissue

Stem cells that respond to injury or infection
-- Differentiate into fibroblasts, macrophages, etc.
--- Produce other types of tissue cells

Derived from embryonic mesenchyme

Front 92

Macrophages

Back 92

Large, amoeba-like cells of the immune system

Functions to engulf pathogens and damaged cells
-- (undergo phagocytosis to swallow up diseases to break
them down and keep them from spreading)

Two Classes:
1. Fixed Macrophages
2. Free Macrophages

Front 93

Fixed Macrophages

Back 93

Stay in tissue

Frontline defense, reinforced by free macrophages and other cells

Front 94

Free Macrophages

Back 94

migrate through tissue

Front 95

Mast Cells

Back 95

Stimulate inflammation after injury or infection

- Release histamine and heparin

Front 96

Histamine

Back 96

dilates blood vessels

Front 97

Haparin

Back 97

anticoagulant

Front 98

Basophils

Back 98

leukocytes (WBC's) that also contain histamine and heparin

Front 99

leukocytes

Back 99

White blood cells

Front 100

Lymphocytes

Back 100

specialized immune cells in lymphatic (lymphoid) system

Ex: Lymphocytes may develop into plasma cells (plasmocytes) that produce antibodies
-- Vaccines stimulate some lymphocytes to become
plasma cells to produce antibodies

* A subclass of leukocytes (WBC's) and are basically specialized leukocytes

Front 101

Plasmocytes

Back 101

plasma cells that produce antibodies

Front 102

Melanocytes

Back 102

Synthesize and store the brown pigment melanin

-- Located in eye and dermis of skin

Front 103

Mesenchyme

Back 103

Embryonic connective tissue
Embryonic stem cells

- First connective tissue to appear in embryos
- Gives rise to all other connective tissues

*Not found in adults!
-- though many adult connective tissues do have
mesenchymal stem cells for tissue repair

Front 104

Adipose Tissue

Back 104

Contains many adipocytes (fat cells)

- Incapable of dividing!!!!
-- Shrinks when nutrients are scarce (do NOT die)
-- Weight lost at area can be regained

- More produced by mesenchymal cells if needed by dies

Two Types:
1. White Fat
2. Brown Fat

*surrounds organs and can store energy
* can't divide or go through mitosis!

Front 105

Types of Adipose Tissue

Back 105

1. White Fat

2. Brown Fat

Front 106

White Fat

Back 106

* most common

1. Stores fat
2. Absorbs shocks
3. Slows heat loss (insulation)

Front 107

Brown Fat

Back 107

widespread in the fetus and infant (only small amounts in adults

- more vascularized
- Adipocytes have many mitochondria
- When stimulated by nervous system, fat breakdown
speeds up --> releases energy
- Energy is absorbed by surrounding tissues --> heats body/blood

Front 108

Fluid Connective Tissues

Back 108

*Blood and Lymph

Has a watery matrix of dissolved proteins

Carries specific cell types (formed elements)

Front 109

Formed Elements of Blood:

Back 109

1. Red Blood Cells (erythrocytes)

2. White Blood Cells (leukocytes)

3. Platelets

Front 110

Erythrocytes

Back 110

Red Blood Cells

Responsible for the transport of oxygen and carbon dioxide in the blood

Make up 50% blood volume and give blood its color

Front 111

Leukocytes

Back 111

White Blood Cells

** do not confuse leukocytes with lymphocytes (which is a
special TYPE of leukocyte)

Help defend the body from infection and disease

(Monocytes, lymphocytes, eosinophil, neutrophil, basophil)

Front 112

Platelets

Back 112

Are actually not cells but fragments of cells

Cause coagulation (blood clots)
-- Prevents blood loss and decreased blood pressure

Membrane-enclosed packets of cytoplasm --> blood clotting

Front 113

Fluid Elements of Connective Tissues

Back 113

Extracellular Fluid Includes:

1. Plasma

2. Interstitial Fluid

3. Lymph

Front 114

Interstitial Fluid

Back 114

a type of extracellular fluid

Front 115

Lymph

Back 115

Fluid that is created when blood pushes fluid out of capillaries

Extracellular fluid collected from interstitial space (leftover fluid from the capillaries)

- Monitored by immune system
- Transported by lymphatic (lymphoid system)
- Returned to venous system (cardiovascular system)

Front 116

Supporting Connective Tissues:

Back 116

1. Cartilage

2. Bone

support soft tissues and body weight

Front 117

Cartilage

Back 117

Gel-type ground substance

Used for shock absorption and protection

- produced by chondrocytes
- avascular

Front 118

Bone (osseous tissue)

Back 118

Calcified (made rigid by calcium salts, minerals)

Used for weight support

Maintained by osteocytes

- Strong (calcified calcium salt deposits)
- Resists shattering (flexible collagen fibers)

Front 119

Chondrocytes

Back 119

Produce cartilage

Produce antiagiogenesis factor (prevents blood vessel formation --> slow repair of damaged cartilage)

Front 120

Membranes

Back 120

- Physical Barriers
-- Prevents foreign material from entering and nutrients
from leaving
- Line or cover portions of the body

Consist of:
1. An epithelium
2. Supported by connective tissue

Front 121

Four Types of Membranes

Back 121

1. Mucous Membranes
2. Serous Membranes
3. Cutaneous Membranes
4. Synovial Membranes

**Mucous, serous, and cutaneous membranes are al
epithelial tissue

Front 122

Mucous Membranes (Mucosae)

Back 122

- Line passageways that have external connections
- In digestive, respiratory, urinary, and reproductive tracts
- Epithelial surfaces must be moist
-- To reduce friction
-- To facilitate absorption and excretion
- Lamina propria supports it

Have a layer of mucous that protects them from the external environment (reduces friction, facilitates absorption and excretion)

Front 123

Lamina Propria

Back 123

connective tissue component that supports the superior epithelial tissues

Front 124

Serous Membranes

Back 124

- Line cavities not open/exposed to the outside
- Are thin but strong
- Have fluid called transudate
- Two Layers (with fluid in between)
1. Parietal
2. Visceral

Ex: pericardium, etc.

Front 125

Transudate

Back 125

a fluid in serous membranes that is used to reduce friction and lubricate the membrane

Front 126

Parietal layer

Back 126

layer of serous membranes that cover the body cavity

Front 127

Visceral Layer (serosa)

Back 127

layer of serous membranes that cover the organs

Front 128

Types of Serous Membranes

Back 128

1. Pleura

2. Peritoneum

3. Pericardium

Front 129

Pleura

Back 129

*a type of serous membrane

Parietal: Lines pleural cavities
Visceral: Covers lungs

Front 130

Peritoneum

Back 130

*a type of serous membrane

Parietal: Lines peritoneal cavity
Visceral: Covers abdominal organs

Front 131

Pericardium

Back 131

*a type of serous membrane

Parietal: Lines pericardial cavity
Visceral: Covers heart

Front 132

Cutaneous Membranes

Back 132

Skin
- found on the surface of the body

- Thick
- "Waterproof"
- Dry

Front 133

Synovial Membranes

Back 133

line moving, articulating joint cavities

Synoviocytes line cavity, produce synovial fluid (lubricant)

- Protect the ends of bones
- Lack a true epithelium

Front 134

Synoviocytes

Back 134

sparsely dispersed cells that line cavities and produce lubricating synovial fluid

Front 135

Functions of Connective Tissues:

Back 135

1. Provide Strength and Stability
2. Maintain positions of internal organs
3. Provide routes for blood vessels, lymphatic vessels, and
nerves

Front 136

Fascie

Back 136

different layers of connective tissue

singular: fascia

- The body's framework of connective tissue
- Layers and wrappings that support or surround organs

Front 137

Three Types of Fasciae

Back 137

1. Superficial Fascia (hypodermis)

2. Deep Fascia

3. Subserous Fascia

Front 138

Superficial Fascia

Back 138

hypodermis

provides insulation and padding

Front 139

Deep Fascia

Back 139

resist multidirectional forces

bound to capsules around most organs, tendons, and ligaments

Front 140

Subserous Fascia

Back 140

protects body cavity lining when muscles/muscular organs move

Front 141

Muscle Tissue

Back 141

- Specialized for Contraction
- Produces all body Movement

3 Types (Skeletal, cardiac, smooth)

Front 142

Types of Muscle Tissue:

Back 142

1. Skeletal Muscle Tissue

2. Cardiac Muscle Tissue

3. Smooth Muscle Tissue

Front 143

Skeletal Muscle Tissue

Back 143

large body muscles responsible for VOLUNTARY movement

Front 144

Cardiac muscle Tissue

Back 144

Found only in the heart

INVOLUNTARY

Front 145

Smooth Muscle Tissue

Back 145

Found in walls of hollow, contracting organs (blood vessels, urinary bladder, respiratory, digestive, and reproductive tracts)

INVOLUNTARY

Front 146

Classifications of Muscle Cells:

Back 146

1. Striated vs. Non-striated

2. Single Nucleus vs. Multinucleate

3. Voluntary vs. Involuntary

Front 147

Striated

Back 147

muscle cells with a banded appearance

Front 148

Non-striated

Back 148

not banded; smooth muscle

Front 149

Multinucleate

Back 149

multiple nuclei

Ex: Skeletal Muscle

Front 150

Voluntary

Back 150

conscious control

Front 151

Involuntary

Back 151

automatic control

Front 152

Skeletal Muscle Cells

Back 152

- Long and Thin
- Striated
- Multi-nucleated

- Usually called muscle fibers
- Do NOT divide
-- but new fibers are produced by stem cells (myosatellite
cells) --> Low Repair Ability

Front 153

Myosatellite Cells

Back 153

repair damaged muscle cells, but do NOT replace those fibers

Front 154

Cardiac Muscle Cells

Back 154

- Striated
- Single Nucleus
- Cardiocytes

Form branching networks connected at intercalated discs (contains gap junctions)

Front 155

Smooth Muscle Cells

Back 155

- Non-striated
- Small and tapered
- CAN divide and regenerate

Front 156

Neural Tissue (nervous/nerve tissue)

Back 156

- Specialized for conducting electrical impulses
-- Sends electrical signals to other cells through a cell
process called an axon
- Rapidly senses internal or external environment
- Processes information and controls responses
- Neural tissue is concentrated in the CNS

Front 157

Central Nervous System

Back 157

brain and spinal cord

Front 158

Types of Neural Cells:

Back 158

1. Neurons

2. Neuroglia

Front 159

Neurons

Back 159

nerve cells

Perform electrical communication
-- Send and receive impulses/commands

Front 160

Neuroglia

Back 160

supporting cells

Repair and supply nutrients to neurons
- Clean up to keep environment healthy and nice