chapter 4 - Tissues Flashcards
1
Q
Q: What is a tissue?
A
A: A tissue is a group of similar cells that usually have a common embryonic origin and work together to perform specialized functions.
2
Q
Q: What are the four basic types of tissues in the human body?
A
A: The four basic types are epithelial, connective, muscular, and nervous tissues, categorized according to their structure and function.
3
Q
Q: What is histology?
A
A: Histology is the study of tissues.
4
Q
Q: Who is a pathologist?
A
A: A pathologist is a doctor who examines tissues to diagnose diseases.
5
Q
Q: What is the function of epithelial tissue?
A
A: Epithelial tissue covers surfaces, lines organs and cavities, and forms glands, enabling interaction with the environment.
6
Q
Q: What is the function of connective tissue?
A
A: Connective tissue supports and protects the body, binds organs, stores energy as fat, and offers disease protection.
7
Q
Q: What is muscular tissue made of, and what is its function?
A
A: Muscular tissue is made of cells that contract to produce movement and heat.
8
Q
Q: What does nervous tissue do?
A
A: Nervous tissue senses changes and generates signals to trigger responses in muscles and glands.
9
Q
Q: What is a cell junction?
A
A: A cell junction is a point of contact between the plasma membranes of tissue cells, allowing them to form functional units.
10
Q
Q: Why are cell junctions important in tissues?
A
A: They allow cells to connect and work together, forming tightly joined structures in epithelial, muscle, and nerve tissues.
11
Q
Q: What is the function of tight junctions?
A
A: Tight junctions seal cells together to prevent the leakage of substances between them.
12
Q
Q: What is the role of adhering junctions?
A
A: Adhering junctions provide strong mechanical attachments between cells.
Help resist cell separation during muscle activity (i.e. food passing through GI tract)
13
Q
Q: How do desmosomes function?
A
A: Additional strength to hold cells together. Prevent cells from spreading (i.e. epidermis of skin)
14
Q
Q: What is the purpose of hemidesmosomes?
A
A: Hemidesmosomes attach cells to the basement membrane.
15
Q
Q: What role do gap junctions play?
A
A: Gap junctions allow communication between cells by enabling the passage of ions and small molecules.
16
Q
Q: How are tight junctions formed?
A
A: Tight junctions are created by weblike strands of transmembrane proteins that fuse the outer surfaces of adjacent cell membranes.
17
Q
Q: What is the function of tight junctions?
A
A: They seal off pathways between cells, preventing substances from passing through and stopping cell contents from leaking into the blood and surrounding tissues.
18
Q
Q: Where are tight junctions commonly found?
A
A: They are abundant in epithelial cells lining the stomach, intestines, and bladder, helping to maintain the integrity of these organs’ contents and prevent leaks.
19
Q
Q: What is the structure of adhering junctions?
A
A: Adhering junctions feature a protein layer called plaque on the inside of the cell membrane, connecting to membrane proteins and cytoskeleton microfilaments.
20
Q
Q: What proteins are involved in adhering junctions, and how do they function?
A
Adhering junctions use proteins called cadherins. These proteins extend from one cell, cross the gap between cells, and connect to cadherins on neighboring cells.
21
Q
Q: What is the role of cadherins in adhering junctions?
A
A: Cadherins join cells together by connecting across the space between cell membranes, providing structural integrity.
22
Q
Q: How do adhering junctions help epithelial tissues?
A
A: They form adhesive belts around epithelial cells, helping tissues resist separation during movements, such as when food passes through the intestines.
23
Q
Q: What are microfilaments, and what is their role in adhering junctions?
A
A: Microfilaments, or actin filaments, are the thinnest filaments of the cytoskeleton, composed of the protein actin. They are involved in adhering junctions by attaching to the plaque and aiding in structural resistance.
24
Q
Q: What is the structure of desmosomes?
A
A: Desmosomes contain a plaque (a dense layer of proteins on the inside of the plasma membrane) that attaches to membrane proteins and intermediate filaments containing keratin.
25
Q: How do desmosomes differ from adhering junctions in terms of cytoskeletal attachment?
A: Unlike adhering junctions, desmosomes connect to intermediate filaments (keratin) rather than microfilaments.
26
Q: What is the function of keratin in desmosomes?
A: Keratin filaments span the cell, connecting desmosomes on opposite sides, and enhance cell and tissue stability.
27
Q: Where are desmosomes commonly found, and what is their role?
A: Desmosomes are prevalent in the epidermis and cardiac muscle, where they prevent cells from separating under stress, such as during heart contractions or skin movement.
28
Q: How do desmosomes contribute to tissue integrity?
A: They provide mechanical strength to tissues by preventing cell separation and maintaining cellular cohesion under stress.
29
Q: What is the primary function of hemidesmosomes?
A: Hemidesmosomes anchor cells to the basement membrane rather than connecting adjacent cells.
30
Q: How do hemidesmosomes differ from desmosomes in terms of connection?
A: Unlike desmosomes, hemidesmosomes do not link adjacent cells; they instead anchor cells to the basement membrane.
31
Q: What transmembrane proteins are used in hemidesmosomes?
A: Hemidesmosomes use integrins as their transmembrane proteins, rather than cadherins.
32
Q: What role does laminin play in hemidesmosomes?
A: Laminin, a glycoprotein in the extracellular matrix, provides a structural foundation by linking with integrins to stabilize and anchor cells to the basement membrane.
33
Q: What are gap junctions?
A: Gap junctions are tiny fluid-filled channels that connect nearby cells, allowing ions and small molecules to pass between them.
34
Q: What proteins form gap junctions?
A: Gap junctions are formed by proteins called connexins.
35
Q: What is the key function of gap junctions in cellular communication?
A: They facilitate communication between cells, enabling the exchange of nutrients and waste, and supporting the rapid spread of nerve and muscle impulses.
36
Q: Where are gap junctions particularly important, and why?
A: They are important in areas like the lens and cornea of the eye where there are no blood vessels, and for coordinated activities in the heart, nervous system, gastrointestinal tract, and uterus.
37
Q: How do gap junctions function in embryo development?
A: They help transfer signals that control growth and differentiation, aiding in embryonic development.
38
Q: What is simple epithelium?
A: A single layer of cells involved in diffusion, filtration, secretion, or absorption.
39
Q: What are squamous cells and their function?
A: Flat and thin cells that allow rapid passage of substances.
39
Q: What is stratified epithelium?
A: Multiple layers of cells providing protection in areas of high wear and tear.
39
Q: What is pseudostratified epithelium?
A: It looks like multiple layers due to varying nucleus levels but is actually a single layer. Some of these cells may have cilia or secrete mucus.
40
Q: Describe cuboidal cells and their function.
A: Cube-shaped cells, as tall as they are wide, often with microvilli, involved in secretion or absorption.
41
Q: What are columnar cells and their specialized features?
A: Tall, column-shaped cells providing protection, possibly having cilia or microvilli, and specialized for secretion and absorption.
42
Q: What are transitional cells?
A: Cells that can change shape from squamous to cuboidal as organs like the bladder stretch and contract.
43
Q: What are the two main types of epithelial tissue?
A: Surface epithelium and glandular epithelium.
44
Q: What is the function of surface epithelium?
A: It covers the body’s external surfaces, lines internal organs, forms the lining of body cavities, and covers systems such as the respiratory, digestive, and reproductive systems.
45
Q: What role does glandular epithelium play?
A: It makes up parts of glands responsible for secretion, such as the thyroid, adrenal, and sweat glands.
46
Q: What are the primary functions of epithelial tissue?
A: Protection, secretion, absorption, and excretion.
47
Q: Describe the structural elements of epithelial tissue.
A: It consists of cells arranged in continuous sheets, densely packed with minimal space, and is avascular but contains a nerve supply.
48
Q: How is the apical surface of epithelial tissue oriented and what is its function?
A: It faces outward towards a body surface or cavity and functions in protection and absorption.
49
Q: What do the lateral surfaces of epithelial cells do?
A: They connect to adjacent cells through junctions like tight junctions and desmosomes.
50
Q: What is the basal surface and its role?
A: The basal surface faces inward and attaches to the basement membrane, anchoring the epithelium.
51
Q: What is the basement membrane?
A: A thin, fibrous layer of extracellular matrix that sits between epithelial tissue and the underlying connective tissue.
52
Q: Why is epithelial tissue described as avascular?
A: It does not contain blood vessels but is supplied by nerves. It relies on diffusion from underlying connective tissues for nutrients.
53
Q: How is surface epithelium classified?
A: It is classified based on the arrangement of cells in layers and their shapes.
54
Q: What defines simple epithelium?
A: Simple epithelium consists of a single layer of cells and functions in processes like diffusion, osmosis, filtration, secretion, and absorption.
55
Q: What are the primary functions of simple epithelium?
A: It facilitates diffusion, osmosis, filtration, secretion, and absorption.
56
Q: What is secretion in the context of epithelial tissue?
A: The production and release of substances such as mucus, sweat, or enzymes.
57
Q: Define absorption in epithelial tissue.
A: The intake of fluids or other substances, like digested food from the intestinal tract.
58
Q: How are covering and lining epithelia further classified?
A: They are classified according to the shape of the cells and how many layers thick they are.
59
Q: What is pseudostratified epithelium and how does it function?
A: Pseudostratified epithelium appears to have multiple layers due to nuclei at different levels but is actually a single layer. All cells rest on the basement membrane, with some having cilia or being goblet cells that secrete mucus.
60
Q: What characterizes stratified epithelium?
A: Stratified epithelium consists of two or more layers of cells that provide protection for underlying tissues in areas of considerable wear and tear.
61
Q: Describe squamous cells and their function.
A: Squamous cells are flat and thin, allowing for the rapid passage of substances through them.
62
Q: What are the characteristics and functions of cuboidal cells?
A: Cuboidal cells are cube or hexagon-shaped, as tall as they are wide, and may have microvilli. They function in secretion or absorption.
63
Q: How do columnar cells differ in shape and function?
A: Columnar cells are much taller than they are wide, like columns, and protect underlying tissues. They may have cilia or microvilli and are often specialized for secretion and absorption.
64
Q: What are the main functions of connective tissue in relation to support?
A: Connective tissue binds, supports, and strengthens other tissues.
65
Q: How does connective tissue protect and insulate the body?
A: It shields and insulates internal organs.
66
Q: What role does connective tissue play in compartmentalization?
A: It separates structures, such as skeletal muscles, into compartments.
67
Q: How does connective tissue function as a transport system?
A: Blood, a connective tissue, serves as the body's main transport system.
68
Q: Why is connective tissue important for blood vessel distribution?
A: It houses and distributes most blood vessels throughout the body.
69
Q: What is the role of connective tissue in energy storage?
A: Connective tissue stores energy reserves, such as in adipose (fat) tissue.
70
Q: How does connective tissue contribute to immune responses?
A: It serves as a primary site for immune function, aiding in the body's defense.
71
Q: What are the two main components of connective tissue?
A: The extracellular matrix and cells.
72
Q: What is the extracellular matrix in connective tissue, and what does it include?
A: The extracellular matrix is the material between connective tissue cells, consisting of protein fibers and ground substance. It largely determines the tissue's properties.
73
Q: How does the extracellular matrix differ among various connective tissues?
A: It can be firm but flexible in cartilage and hard and rigid in bone.
74
Q: Where is connective tissue not typically located?
not typically found on body surfaces.
75
Q: How does the blood supply of connective tissue usually compare to other tissues?
A: Connective tissue usually has a rich blood supply, making it highly vascular, except for cartilage (which lacks blood vessels) and tendons (which have limited blood flow).
76
Q: What is unique about the nerve supply in connective tissues?
A: Most connective tissues have a nerve supply, which differs from some other tissues.
77
Q: What embryonic cells do connective tissues originate from?
A: Mesenchymal cells.
78
Q: What is the role of fibroblasts in connective tissue?
A: They are large, flat cells responsible for producing fibers and secreting the extracellular matrix in loose and dense connective tissues.
79
Q: What happens to "-blast" cells as they mature in connective tissue?
A: They become "-cytes" (e.g., fibrocytes, chondrocytes, osteocytes), focusing on maintaining the matrix rather than forming it.
80
Q: Describe the function of macrophages in connective tissue.
A: Derived from white blood cells, they perform phagocytosis to defend against infections, with some roaming and others fixed in tissues like the lungs or spleen.
81
Q: What are plasmocytes (plasma cells), and what do they do?
A: Derived from B lymphocytes, they produce antibodies, residing in connective tissues, especially in the digestive and respiratory tracts.
82
Q: What role do mast cells play in connective tissue?
A: They participate in the inflammatory response and can destroy bacteria, releasing histamine during allergic reactions.
83
Q: What are adipocytes, and where are they located?
A: Fat cells that store triglycerides, found under the skin and around organs like the heart and kidneys.
84
Q: How do leukocytes function in connective tissue? Give examples.
A: Though normally few in connective tissue, they migrate there during infections or allergic reactions. Neutrophils respond to infections, and eosinophils handle parasitic infections and allergic reactions.
85
Q: What are reticular fibers, and their function?
A: Thin, supportive fibers made of collagen and glycoproteins, forming networks around cells.
86
Q: Define the ground substance in connective tissue.
A: The medium between cells and fibers, aiding in nutrient exchange and housing various substances.
87
Q: What are the two main components of the extracellular matrix in connective tissue?
A: Ground substance and fibers.
88
Q: What is the function of the ground substance in connective tissue?
A: It fills the space between cells and fibers, determining the matrix's consistency, which can be fluid, gel-like, or solid.
89
Q: What role do collagen fibers play in connective tissue?
A: They provide strength and flexibility without being too rigid, resisting stretching while allowing flexibility.
90
Q: Where are collagen fibers commonly found?
A: In bone, cartilage, tendons, and ligaments.
91
Q: Describe the structure of collagen fibers.
A: Made of collagen protein, organized in parallel bundles for tensile strength.
92
Q: What is unique about collagen fibers in cartilage compared to bone?
A: They are surrounded by more water in cartilage, offering a cushioning effect.
93
Q: What is the function of elastic fibers in connective tissue?
A: They provide elasticity, allowing tissues to stretch and return to their original shape.
94
Q: Describe the characteristics and location of elastic fibers.
A: Stretchable up to 150% of their length, abundant in skin, blood vessel walls, and lungs.
95
Q: What do reticular fibers function as in connective tissue?
A: They provide support and strength, forming supportive networks around cells.
96
Q: Where are reticular fibers found, and what is their structure?
A: Found in areolar tissue, adipose tissue, nerve fibers, and smooth muscle, made of collagen coated with glycoprotein, produced by fibroblasts.
97
Q: What special role do reticular fibers play in soft organs?
A: They form the stroma, or supporting framework, of soft organs like the spleen and lymph nodes.
98
Q: What are the two main categories of connective tissue?
A: Embryonic and mature connective tissue.
99
Q: What is mesenchyme, and where is it found?
A: Mesenchyme is an embryonic connective tissue found primarily in embryos and develops into all other types of connective tissue.
100
Q: What is mucoid (mucous) connective tissue, and what is its function?
A: It is present in the fetus and provides support in certain fetal structures.
101
Q: What are the two subcategories of mature connective tissue?
A: Supporting connective tissue and liquid connective tissue.
102
Q: Name and describe different types of cartilage within supporting connective tissue.
Hyaline Cartilage: Provides smooth surfaces for movement at joints.
Fibrous Cartilage: The strongest type, absorbs shock (e.g., intervertebral discs).
Elastic Cartilage: Provides strength and elasticity (e.g., ear).
103
Q: What are the characteristics of compact bone?
A: Compact bone is dense and strong, forming the outer layer of bones.
104
Q: Describe spongy bone and its function.
A: Spongy bone is porous and lighter, found inside bones, providing structural support and flexibility.
105
Q: What is the function of blood as a liquid connective tissue?
A: Blood transports nutrients and waste, with plasma as its liquid matrix.
106
Q: What are chondrocytes and their primary role in cartilage?
A: Chondrocytes are the cells of mature cartilage responsible for maintaining the cartilage structure and producing components like collagen within spaces called cartilage lacunae.
107
Q: What are the main components of cartilage?
A: Cartilage consists of a dense network of collagen fibers or elastic fibers embedded in chondroitin sulfate, the gel-like component of the ground substance.
108
Q: Where does the strength and resilience of cartilage come from?
A: The strength of cartilage comes from collagen fibers, while its resilience (ability to return to shape after deformation) comes from chondroitin sulfate.
109
Q: How is cartilage different from other connective tissues in terms of blood supply and innervation?
A: Cartilage is avascular, meaning it lacks nerves and blood vessels in its extracellular matrix. It secretes an antiangiogenetic factor to prevent blood vessel growth.
110
what is chondroitin sulfate in terms of cartilage?
the gel-like component of the ground substance.
Cartilage consists of a dense network of collagen fibers or elastic fibers embedded in chondroitin sulfate
111
Q: How does hyaline cartilage appear, and what is its composition?
A: It appears bluish-white and shiny, with a gel-like ground substance. It contains fine collagen fibers not visible under standard microscopy and prominent chondrocytes in lacunae.
112
Q: Where is hyaline cartilage located?
A: It's the most common type of cartilage, found at the ends of long bones, ribs, nose, parts of the larynx, trachea, bronchi, and the fetal skeleton.
113
Q: What functions does hyaline cartilage serve?
A: It provides smooth surfaces for joint movement, flexibility, and support, although it is the weakest type of cartilage.
114
Q: What distinguishes fibrous cartilage in terms of structure?
A: It contains chondrocytes among thick, visible bundles of collagen fibers and does not have a perichondrium.
115
Q: Where can you find fibrous cartilage?
A: It is located in the pubic symphysis, intervertebral discs, menisci of the knee, and where tendons insert into cartilage.
116
Q: What are the functions of fibrous cartilage?
A: It provides strong support and joins structures together, known for its strength and rigidity.
117
Q: Describe the structure of elastic cartilage.
A: It has chondrocytes within a threadlike network of elastic fibers and is surrounded by a perichondrium.
118
Q: What are the typical locations of elastic cartilage?
A: Found in the epiglottis, external ear (auricle), and auditory tubes.
119
what are the three types of muscle tissue?
skeletal, cardiac, smooth muscle
120
Q: What is the primary function of muscular tissue?
A: Provides motion, maintains posture, and produces heat.
121
Q: What type of cells compose muscular tissue?
A: Elongated cells known as muscle fibers or myocytes.
122
Q: How do muscle fibers produce force?
A: They use ATP to produce force.
123
Q: Where is skeletal muscle located?
A: Attached to bones.
124
Q: What are the features of skeletal muscle?
A: Voluntary control, striated appearance.
125
Q: What is the function of skeletal muscle?
A: Facilitates body movement and maintains posture.
126
Q: Where is cardiac muscle found?
A: In the walls of the heart.
127
Q: What is the function of cardiac muscle?
A: Pumps blood throughout the body.
128
Q: Where is smooth muscle located?
A: In the walls of hollow organs like intestines and blood vessels.
129
Q: What are the features of smooth muscle?
A: Involuntary control, non-striated, spindle-shaped cells.
130
Q: What is the function of smooth muscle?
A: Moves substances through organs, regulates blood vessel diameter, and controls passages like airways.
131
Q: What is muscular tissue composed of?
A: Elongated cells known as muscle fibers or myocytes.
132
Q: What is the role of ATP in muscle fibers?
A: Produces force to enable movement, posture maintenance, heat generation, and protection.
133
skeletal muscle tissue description:
- Consists of long, cylindrical, striated fibers.
- Muscle fibers can be short or quite long, up to 30-40 cm.
- Each fiber is multinucleated, with nuclei located at the edges.
- This type of muscle is voluntary, meaning it can be consciously controlled to contract or relax.
134
Each ___ ____ fiber is multinucleated, with nuclei located at the edges.
Each Skeletal Muscle Fiber is multinucleated, with nuclei located at the edges.
135
___ ___ usually attaches to bones by tendons
Skeletal Muscle usually attaches to bones by tendons.
136
Responsible for motion, posture, heat protection, and overall protection.
Muscle Tissue
137
Q: What type of muscle fibers compose skeletal muscle tissue?
A: Striated muscle fibers.
138
Q: What supports skeletal muscle tissue?
A: Connective tissue.
139
Q: How is skeletal muscle attached to a bone?
A: By a tendon or an aponeurosis.
140
Q: What stimulates skeletal muscle?
A: Somatic motor neurons.
141
Q: What is the structure of cardiac muscle fibers?
A: Branched, striated fibers with usually one centrally located nucleus.
142
Q: How are cardiac muscle fibers connected?
A: They attach end to end by intercalated discs.
143
Q: What do intercalated discs contain?
A: Desmosomes and gap junctions.
144
Q: What is the function of desmosomes in cardiac muscle?
A: They strengthen the tissue and hold fibers together during vigorous contractions.
145
Q: What role do gap junctions play in cardiac muscle?
A: They provide a route for quick conduction of electrical signals throughout the heart.
146
Q: Is cardiac muscle under voluntary or involuntary control?
A: Involuntary control.
147
Q: Where is cardiac muscle located?
A: It forms the wall of the heart.
148
Q: What stimulates cardiac muscle?
A: An intrinsic conduction system and autonomic motor neurons.
149
where is the location of cardiac muscle tissue?
heart wall
150
function of cardiac muscle tissue
pumps blood to all parts of the body
151
what is cardiac muscle stimulated by?
intrinsic conduction system and autonomic motor neurons
152
what are the two kinds of nervous tissue cells?
neurons and neuroglia
153
Q: What are the three main structural parts of a neuron?
A: Cell body, dendrites, and axon.
154
Q: What is the function of neurons?
A: Respond to stimuli and transmit electrical signals called nerve impulses.
155
Q: What functions can neurons perform besides carrying sensory or motor information?
A: Integrative functions.
156
Q: What is the role of the cell body in a neuron?
Q: What is the role of the cell body in a neuron?
157
Q: What do dendrites do in a neuron?
A: Receive signals from other neurons.
158
Q: What is the function of an axon?
A: Sends impulses to other neurons, muscles, or glands.
159
Q: What is the primary role of neuroglia?
A: Protect and support neurons.
160
Q: Do neuroglia conduct nerve impulses?
A: No, they do not conduct impulses.
161
Q: What additional roles do neuroglia have?
A: They provide nutrient supply, waste removal, and structural support.
162
Q: What are the structural parts of a neuron?
A: A cell body and processes extending from the cell body, including one to multiple dendrites and a single axon.
163
Q: What is the primary function of neurons in nervous tissue?
A: To initiate and conduct nerve impulses to coordinate homeostasis.
164
Q: Do neuroglia generate or conduct nerve impulses?
A: No, neuroglia do not generate or conduct nerve impulses.
165
Q: What role do neuroglia play in nervous tissue?
A: They provide support and nourishment to neurons.
166
what are classified as excitable cells and why?
Neurons and muscle fibers are classified as excitable cells because they can generate electrical signals called action potentials in response to stimuli.
167
what defines muscle and fibers as excitable cells?
they generate electrical signals called action potentials in response to stimuli
168
what are action potentials?
electrical signals that move along the cells plasma membrane, enabled by voltage-gated ion channels.
169
Q: What happens in neurons when an action potential occurs?
A: The neuron releases neurotransmitters, which facilitate communication between neurons and with muscles or glands.
170
Q: What is the role of action potentials in muscle fibers?
A: They trigger muscle contraction, leading to actions like limb movement, intestinal food propulsion, and heart-driven blood circulation.
171
Q: Why is electrical excitability important for neurons and muscle fibers?
A: It allows these cells to perform their essential roles in bodily functions through the production of action potentials.
172
Q: What enables the travel of action potentials along the plasma membrane?
A: The presence of specific voltage-gated channels in the cell membrane.
173
Q: What is tissue repair?
A: The process that replaces worn-out, damaged, or dead cells.
174
Q: How do new cells originate during tissue repair?
A: By cell division from the stroma (supporting connective tissue) or the parenchyma (functioning part of the tissue or organ).
175
Q: How are epithelial cells replaced?
A: By the division of stem cells or undifferentiated cells.
176
Q: Do all connective tissue cells have the ability to repair?
A: No, some connective tissues like bone can renew continuously, but tissues like cartilage have less capability due to a smaller blood supply.
177
Q: Can muscle cells perform repair?
A: Yes, but it is limited. Skeletal muscle stem cells divide slowly, cardiac muscle lacks satellite cells, but stem cells can migrate from the blood, and smooth muscle can proliferate slowly.
178
Q: Can nervous cells perform repair?
A: Some can perform limited repair, while others cannot. The brain has some stem cells but they usually do not replace damaged neurons.
179
Q: What is fibrosis?
A: The formation of scar tissue, a process where active fibroblasts in the stroma produce new connective tissue.
