Cecie Starr | Beverly McMillan Chapter 4 Tissues, Organs, and Organ Systems.
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Transcript of Cecie Starr | Beverly McMillan Chapter 4 Tissues, Organs, and Organ Systems.
Cecie Starr | Beverly McMillan
Chapter 4
Tissues, Organs, and Organ Systems
Key Concepts•Types of Body Tissues•Organs and Organ Systems•Homeostasis
Tissues, Organs, and Organ Systems 4
Tissues, Organs, and Organ Systems 4
• Stem cells– Embryonic stem cells:
controversy– Adult stem cells
p67
4.1 Epithelium: The Body’s Covering and Linings
• Epithelial tissues cover the body surface or line it’s cavities and tubes
Types of Body Tissues
4.1 Epithelium: The Body’s Covering and Linings
• Epithelium – Simple: one layer of cells– Stratified: several layers of cells
• Shape of the cells at the tissue’s free surface– Squamous epithelium– Cuboidal epithelium– Columnar epithelium
• Basement membrane
There are two basic types of epithelia.
4.1 Epithelium: The Body’s Covering and Linings
simple squamous epithelium
basement membrane
connective tissue
free surface of epithelium
Flattened simple squamous epithelium
Squarish simple cuboidal epithelium
Tall simple columnar cellsFigure 4-1 p68
4.1 Epithelium: The Body’s Covering and Linings
• Gland– Make and release specific products– Derived from epithelial tissue
• Classification– Exocrine gland
• Substances released through ducts or tubes– Endocrine gland
• Substances released directly into the extracellular fluid
Glands form from epithelium.
4.1 Epithelium: The Body’s Covering and Linings
parotid gland(secretes saliva)
Exocrine gland
parotid duct (deliverssaliva to mouth)
thyroid gland (secreteshormones into blood)
Endocrine gland
bloodvessel
cell that secreteshormone
Figure 4-2 p69
Take home message
What are epithelial tissues?
4.2 Connective Tissue: Binding, Support, and Other Roles
• Connective tissue connects, supports, and anchors the body’s parts
• Makes up more of your body than any other tissue
• Fibrous and specialized types
• Matrix– Ranges from hard to liquid
4.2 Connective Tissue: Binding, Support, and Other Roles
• Fibrous connective tissue
• Loose connective tissue– Flexible
• Dense connective tissues– Less flexible; stronger
• Elastic connective tissue– Stretchy due to elastin
Fibrous connective tissues are strong and stretchy.
Table 4-1 p69
Table 4-2 p70
4.2 Connective Tissue: Binding, Support, and Other Roles
collagenous fiberfibroblastelastic fiber
Type Loose connective tissue Description Fibroblasts, other cells, plus fibers loosely arranged in semifluid matrix Common Locations Under the skin and most epithelia Function Elasticity, diffusion
collagenous fibers
Type Dense, irregular connective tissue Description Collagenous fibers, fibroblasts, less matrix Common Locations In skin and capsules around some organs Function Support
Figure 4-3 p70
4.2 Connective Tissue: Binding, Support, and Other Roles
• Cartilage– Hyaline cartilage– Elastic cartilage– Fibrocartilage
• Bone tissue
• Adipose tissue
• Blood
Special connective tissues include cartilage, bone, adipose tissue, and blood.
4.2 Connective Tissue: Binding, Support, and Other Roles
collagenous fibers
fibroblast
Type Dense, regular connective tissue Description Collagen fibers in parallel bundles, long rows of fibroblasts, little matrix Common Locations Tendons, ligaments Function Strength, elasticity
ground substance with very fine collagen fiberscartilage cell (chondrocyte)
Type Cartilage Description Cells embedded in pliable, solid matrix Common Locations Ends of long bones, nose, parts of airways, skeleton of embryos Function Support, flexibility, low-friction surface for joint movement Figure 4-3 p70
4.2 Connective Tissue: Binding, Support, and Other Roles
compact bone tissue
nucleusblood vessel
cell bulging with fat droplet
bone cell (osteocyte)
Type Bone tissue Description Collagen fibers, matrix hardened with calcium Common Locations Bones of skeleton Function Movement, support, protection
Type Adipose tissue Description Large, tightly packed fat cells occupying most of matrix Common Locations Under skin, around heart, kidneys Function Energy reserves, insulation, paddingFigure 4-3 p70
4.3 Muscle Tissue: Movement
• Cells in muscle tissue can contract, allowing muscle to move body parts
• Muscle tissue- contracts and shortens when stimulated by an outside signal
4.3 Muscle Tissue: Movement
• Skeletal muscle- striated; usually attached to bone; voluntary; multinucleated
• Smooth muscle- tapered; walls of internal organs; involuntary; uninucleated
• Cardiac muscle- cardiac wall; branching: special cellular junctions (intercalated discs); involuntary; uninucleated
Take home message
What is muscle tissue?
Figure 4-4 p71
white blood cell
platelet
red blood cell
4.3 Muscle Tissue: Movement
nucleus
VOLUNTARY
A Skeletal muscle
nucleus
INVOLUNTARY
B Smooth muscle
adjoining ends of abutting cells
C Cardiac muscle
Figure 4-5 p72
4.4 Nervous Tissue: Communication
• Nervous tissue makes up the nervous system– Neurons (nerve cells)– Neuroglia (support cells)
• Communication lines; carry messages
4.4 Nervous Tissue: Communication
• Glial cells (neuroglia) – 90% of the cells of the
nervous system– Bring nutrients to the
neurons– Physically support neuron– Remove debris– Myelin Sheath
(Schwann cells)• Provide insulation
p73
4.4 Nervous Tissue: Communication
• Neurons have a cell body that contains a nucleus and cytoplasm
• Cell processes– Dendrites– Axons
p73
Take home message
What is nervous tissue?
4.5 Healing with Stem Cells and Lab-Grown Tissues
• “Reverse engineering” mature cells to convert them back to stem cells
• Introduce “cured” stem cells to replace faulty stem cells
• Use stem cells from bone marrow and umbilical cords
• Use a cultured skin substitute
stemcell
stemcell
stemcell
stemcell
stemcell
or
or
celltype 1
celltype 2
celltype 3
cells divide cells specialize
p73
Figure 4-6 p73
4.6 Cell Junctions: Holding Tissues Together
• Junctions between the cells in a tissue knit the cells firmly together, stop leaks, and serve as communication channels
4.6 Cell Junctions: Holding Tissues Together
• Tight junctions– Block leaking between adjoining cells
• Adhering junctions– Desmosomes– Cement cells together
• Gap junctions – Channels that connect the cytoplasm of neighboring cells– Abundant in smooth and cardiac muscle
Take home messageWhat do cell junctions do?
4.6 Cell Junctions: Holding Tissues Together
cell
basementmembrane
Figure 4-7 (top) p74
4.6 Cell Junctions: Holding Tissues Together
Tight JunctionA Adhering JunctionB
cytoskeletonfilaments
plasmamembraneof one cell
Gap JunctionC
channel
Figure 4-7 p74
4.7 Tissue Membranes: Thin, Sheet-like Covers
• Thin, sheet-like membranes cover many body surfaces and cavities
– Some provide protection– Others both protect and lubricate organs
4.7 Tissue Membranes: Thin, Sheet-like Covers
• Mucous membranes– Designed to secrete and/or
absorb substances– Most have glands– Line tubes and cavities
• Serous membranes– Occur in paired sheets; line
the thoracic cavity and enclose the heart and lungs
– Secrete a fluid; no glands
• Cutaneous membranes– Dry membrane; skin
• Synovial membranes– Line cavities of the body’s
movable joints– Lubricate the ends of moving
bones– Prevent friction between a
bone and a moving tendon
Take home message
What are the functions of membranes?
4.7 Tissue Membranes: Thin, Sheet-like Covers
B serous membrane C cutaneous membrane (skin)
D synovial membrane
A mucous membrane
Figure 4-8 p75
4.8 Organs and Organ Systems
• Organ
• Body cavities– Cranial cavity– Spinal cavity– Thoracic cavity– Abdominal cavity– Pelvic cavity
Organs and Organ Systems
4.8 Organs and Organ SystemsOrgan system: A set of organs that interacts to carry out a major body function
Organ: Body structure that integrates different tissues and carries out a specific function
Stomach
Epithelial tissue: Protection, transport, secretion, and absorption
Connective tissue: Structural support
Muscle tissue: Movement
Nervous tissue: Communication, coordination, and controlFigure 4-9a p76
4.8 Organs and Organ Systems
cranial cavity
spinal cavity
thoracic cavity
abdominal cavity
pelvic cavity
Figure 4-9b p76
4.8 Organs and Organ Systems
Organ systems:
Integumentary System
Nervous System
Skeletal System
Muscular System
Circulatory System
Endocrine System
Figure 4-10a p77
4.8 Organs and Organ Systems
Organ systems:
Lymphatic System
Digestive System
Reproductive System
Respiratory System
Urinary System
Figure 4-10a p77
4.9 The Skin: An Example of an Organ System
• Skin– Largest surface area of any organ– Functions
• Oil glands
• Sweat glands
• Hair
• Nails
Skin and structures that develop from it make up the integument- the body’s covering.
4.9 The Skin: An Example of an Organ System
• Epidermis– Stratified squamous
epithelium– Keratinocytes– Melanocytes
• Role in skin color– Langerhans cells– Granstein cells
• Dermis– Dense connective tissue– Elastin and collagen fibers– Blood vessels and nerve
endings– Oil and sweat glands– Hair follicles
Epidermis and dermis are the skin’s two layers.
4.9 The Skin: An Example of an Organ System
smooth muscle
sebaceous gland
hair follicle
sweat gland
epidermisstratifiedsquamousepithelium
dermis mainlydenseconnectivetissue hypodermis mainly adipose tissue and loose connective tissue
pressuresensitivesensoryreceptor
bloodvessel
duct ofsweatgland
hair
Figure 4-11a p78
4.9 The Skin: An Example of an Organ System
outer flattened epidermal cells
cells being flattened
dividing cells
dermis
epidermisstratifiedsquamousepithelium
dermis mainlydenseconnectivetissue
Figure 4-11b p78
4.9 The Skin: An Example of an Organ System
• Hypodermis: layer beneath dermis– Loose connective– Fat: insulator and cushion
4.9 The Skin: An Example of an Organ System
• Sweat glands – Location of glands– Chemical composition of sweat– Role in evaporative cooling
• Oil glands– Location– Sebum: softens and lubricates hair– Effect on bacteria
• Hair– Keratinized cells
Sweat glands and other structures develop from epidermis.
4.9 The Skin: An Example of an Organ System
• Blisters• Acne• Cold sores
• Vitiligo
• Cancer– Squamous cell carcinoma– Malignant melanoma
• Effect of ultraviolet radiation on the skin
Skin disorders are common.
Malignant melanoma
Squamous cell carcinoma
Figure 4-12 p79 p79
Take home message
What is the integumentary system?
4.10 Homeostasis: The Body in Balance
• Cells and more complex body parts function properly only when conditions inside the body are stable
Extracellular fluid
4.10 Homeostasis: The Body in Balance
• Extracellular fluid– ~15 liters– Mostly interstitial fluid– Blood plasma
• Homeostasis– Mechanisms to maintain
stability in the volume and chemical makeup of extracellular fluid
The internal environment is a pool of extracellular fluid.
Interstitial (tissue) fluidCell Blood
Blood vessel
p80
Figure 4-13 p80
Sensors: Cells inthe eyes, ears, skin,and elsewhere
Integrator:The brain
Effectors: Musclesand glands
4.10 Homeostasis: The Body in Balance
• Sensory receptors– Translate the stimulus into a signal that can be sent to
the brain• Stimulus
– Specific change in the external and internal environment
• Integrator– Brain
• Effectors– Muscles and glands
Homeostasis requires the interaction of sensors, integrators, and effectors.
4.10 Homeostasis: The Body in Balance
Stimulus(change in the environment)
In negative feedback, the response of the system cancels or counteracts theeffect of the original change.
Sensor(for example,nerve endingin the skin)
Effector(a muscle
or a gland)
Integrator(such as
the brain)
Response
Figure 4-14 p81
4.10 Homeostasis: The Body in Balance
• Negative feedback– An activity alters a condition in the internal
environment and triggers a response that reverses the altered condition
– Example: keeping body temperature within a normal range
Negative feedback is the most common control mechanism in homeostasis.
4.10 Homeostasis: The Body in Balance
• Positive feedback– A chain of events intensify a change from the original
condition that reverses the change– Example: childbirth
Positive feedback is the plays a role outside of homeostasis.
Homeostasis
Take home message
What are homeostatic controls?
4.11 How Homeostatic Feedback Maintains the Body’s Core Temperature
• Controls over the body’s core temperature provide good examples of negative feedback loops
4.11 How Homeostatic Feedback Maintains the Body’s Core Temperature
• Humans are endotherms.• Core temperature
– 37°C (98.6°F)– Controlled by metabolic activity and negative
feedback loops• What happens to enzyme activity if the body gets too
hot? Too cool?
Body’s core temperature.
4.11 How Homeostatic Feedback Maintains the Body’s Core Temperature
Change in skin temperature Change in core temperature
peripheral thermoreceptors in skin
central thermoreceptors in hypothalamus, abdominal organs, and elsewhere
hormonal signals from “thermostat” centers in hypothalamus
motor neurons
skeletal muscles
smooth muscle in arterioles in skin
sweat glands
voluntary changes in behavior
muscle tone, shivering
vasoconstriction, vasodilation sweating
adjustments in heat gain or heat loss
adjustments in muscle activity (in metabolic heat output)
adjustment in loss or conservation of metabolic heat
adjustment in heat loss
Figure 4-15 p82
4.11 How Homeostatic Feedback Maintains the Body’s Core Temperature
• Hypothalamus- neurons and endocrine cells• Peripheral vasodilation • Activation of sweat glands followed by evaporation of the
sweat• Hyperthermia
– Heat exhaustion– Heat stroke
Excess heat must be eliminated.
Table 4-3 p83
4.11 How Homeostatic Feedback Maintains the Body’s Core Temperature
• Hypothalamus• Peripheral
vasoconstriction • Pilomotor response• Non-shivering heat
production and “brown fat”• Hypothermia and frostbite
Several responses counteract cold.
Metabolic activityat 22°C (72°F)
Metabolic activity aftertwo hours at 16°C (61°F)
Figure 4-16 p83
Take home message
How is body temperature regulated?
Table 4-4 p85