A&P Textbook Chapters 1-5 Flashcards
(211 cards)
1
Q
Explain what causes decompression sickness (DCS) and how it is treated. How does diving in mountain lakes compare to diving at sea level, in terms of DCS?
A
DCS is caused by exposure to an environment where the pressure is rapidly decreasing. This causes dissolved gases (mainly nitrogen) to bubble out of solution in the blood (think of opening a can of soda). DCS mostly affects divers, but also airline pilots in unpressurized cabins. DCS is treated by immediately administering pure oxygen, followed by placement in a hyperbaric chamber. DCS is more likely to happen after diving in a mountain lake.
2
Q
What are the 2 main types of dense connective tissue? What is the main difference between them?
A
Regular = fiber orientation is NOT random, so the tissue is really strong in a particular direction. Examples: ligaments and tendons.
Irregular = fiber orientation IS random, so the tissue is moderately strong in every direction. Example: dermis of skin.
3
Q
Describe fourth-degree burns.
A
It extends all the way to the underlying muscle or bone.
4
Q
What is the difference between simple, stratified, and pseudostratified?
A
Simple = when every cell rests on the basal lamina.
Stratified = there is more than one layer of cells.
Pseudostratified = when there is only one layer of cells, but they are irregularly shaped, so they give the appearance of more than one layer.
5
Q
Define “hole”, in the context of bones.
A
A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone.
6
Q
What is the reticular lamina? Describe it in detail.
A
It is a layer of connective tissue that, together with the basal lamina, forms the basement membrane. It is composed of collagen, secreted by fibroblasts.
7
Q
Which germ layer forms the skeletal system?
A
Mesoderm
8
Q
Which germ layer forms the heart?
A
Mesoderm
9
Q
What are basal cells? What do they do? Where are they found?
A
Basal cells are the precursors to keratinocytes. They are found in the stratum basale. They are constantly dividing (by mitosis) to create new cells, which then push the older cells outward.
10
Q
What is the function of desmosomes?
A
They link adjacent cells together.
11
Q
Which germ layer forms the nails?
A
Ectoderm
12
Q
Name the different types of anchoring junctions.
A
Desmosomes, hemidesmosomes, and adherens.
13
Q
Define pleura.
A
It is the serous membrane that surrounds the lungs in the pleural cavity.
14
Q
What is the function of the hypodermis?
A
It connects the skin to the underlying fascia (fibrous tissue) of the muscles and bones.
15
Q
Describe compact bone.
A
It is the denser, stronger type of bone tissue. It is found in the diaphyses of long bones. The functional unit of compact bone is called an osteon.
16
Q
Define mesothelium.
A
Simple squamous epithelium that forms the surface layer of the serous membranes.
17
Q
What is the basal lamina? Describe it in detail.
A
It is a layer of extracellular matrix that the epithelium sits on. It is a mixture of glycoproteins and collagen. It is secreted by epithelial cells. It constitutes a portion of the basement membrane. It separates the epithelium from the underlying connective tissue.
18
Q
Describe the anatomy of flat bones.
A
They contain a layer of diploë (spongy bone), which is sandwiched between two thin layers of compact bone. This dual layer provides extra protection to the internal organs underneath (if the outer layer of compact bone becomes fractured, the inner layer still provides protection).
19
Q
What is the function of hemidesmosomes?
A
They link cells to the ECM.
20
Q
How do RBCs uptake iron from the bloodstream?
A
They have transferrin receptors on their PMs. These receptors bind to the iron-transferrin complex, and bring the iron in via receptor-mediated endocytosis.
21
Q
What is the transverse plane?
A
It is the plane that divides the body horizontally into upper and lower halves.
22
Q
What is the metaphysis?
A
It is the narrow area of a long bone, where the diaphysis and the epiphysis meets.
It contains the epiphyseal plate.
23
Q
How do calluses form?
A
The basal stem cells in the stratum basale are triggered to divide more. Over time, this causes the skin to thicken.
24
Q
Describe synovial membranes.
A
They are a type of connective tissue membrane that lines the cavity inside a freely movable joint.
25
Define cutaneous membrane.
It is another name for the skin (an epithelial membrane).
26
What is the typical function of simple columnar epithelium?
Secretion and absorption.
27
What type of cell responds to vibration?
Pacinian corpuscles (lamellated corpuscles).
28
Which germ layer forms the serous membranes?
Mesoderm
29
Which germ layer forms the anus?
Ectoderm
30
What is the typical function of stratified epithelium?
It protects against physical and chemical damage.
31
What is jaundice?
The yellowing of the skin, due to accumulation of bile and bilirubin (caused by liver damage, blockage of bile duct, or excessive breakdown of RBCs).
32
Describe the main types of sweat glands.
Eccrine glands produce hypotonic sweat for thermoregulation.
Apocrine glands are found in the groin and armpit areas. In addition to water and salt, they secrete organic compounds that thicken the sweat. These compounds are broken down by bacteria, resulting in odor.
33
Name the 2 types of connective tissue proper. What is the major difference between them?
Loose connective tissue and Dense connective tissue. Dense contains more collagen fibers than Loose does. This means that Dense is more resistant to stretching.
34
What does the prefix "chole-" mean?
Bile.
(cholesterol is a component of bile acids)
35
Name the structural protein found in desmosomes.
Cadherin.
36
Describe the functions of the skin.
It protects against water loss and abrasion. It senses the environment. It helps with thermoregulation (via sweat and vasoconstriction). It synthesizes vitamin D.
37
Name the 2 layers of the dermis, from deep to superficial. Which one is thicker?
Reticular layer (deep; thicker).
Papillary layer (superficial; thinner).
38
Which germ layer forms epithelial cells?
All three of them.
39
What is the function of bone projections?
They serve as attachment points for tendons and ligaments.
40
Describe the function(s) of flat bones. Where are they found?
They serve as attachment points for muscles, and also protect some organs.
Examples: skull, scapulae, sternum, and ribs.
41
Describe the function(s) of short bones. Where are they found?
They provide stability, support, and some limited motion.
They are found in the carpals and tarsals.
42
What is a keloid?
It is a type of scar that is raised. It is caused by an overproduction of scar tissue.
43
Define "ground substance".
It is the major component of extra-cellular matrix. It is often crisscrossed by protein fibers. It is usually a fluid, but can be mineralized and solid (example = bones).
44
Describe branched glands.
In a branched gland, the duct is connected to more than one secretory group of cells.
45
Does bone tissue have a good supply of capillaries? Why or why not?
Yes, because it needs to be in contact with blood.
46
What are two alternate names for the hypodermis?
The subcutaneous layer, or the superficial fascia.
47
Which germ layer forms the kidneys?
Mesoderm
48
Define periosteum.
It is a fibrous membrane that covers the outer surface of bone. It contains blood vessels, lymph vessels, and nerves.
49
What would happen if bones did not contain collagen?
They would be very brittle (the collagen makes bones flexible so they are not brittle).
50
Describe areolar tissue.
It is not very specialized. It contains lots of different cell types and fiber types distributed in a random, web-like fashion.
51
What are dermal papillae? Where are they found?
Dermal papillae are finger-like projections of the papillary layer of the dermis into the epidermis.
52
Describe the composition of connective tissue membranes.
They are formed solely from connective tissue.
53
Name the 3 main types of cartilage tissue.
1. Hyaline cartilage
2. Fibrocartilage
3. Elastic cartilage
54
Name the main causes of burns.
Intense heat, radiation, electricity, and harsh chemicals.
55
Name the types of cells found in the stratum spinosum.
Keratinocytes and Langerhans cells.
56
What is eleidin? What does it do? Where is it found?
Eleidin is a clear protein rich in lipids. It forms a waterproof barrier in the stratum lucidum. It is derived from keratohyalin.
57
Explain how ultrasonography works. What is it used for? What are the advantages and drawbacks?
High-frequency sound waves are transmitted into the body, and the echo signal is recorded by a computer and translated into a real-time image. Ultrasonography is used to study heart function, blood flow in the neck or extremities, gallbladder disease, and fetal development. Advantages: least invasive of all imaging techniques, so can be used in sensitive situations like pregnancy. Drawbacks: image quality depends on operator, and unable to penetrate bone and gas.
58
What is a polyribosome?
It is a string of ribosomes that are all translating the same mRNA simultaneously.
59
Describe third-degree burns.
It extends fully into the epidermis and dermis. It destroys tissues, thus affecting nerve endings.
60
Describe the structure of hair.
Hair is a keratinous filament growing out of the epidermis. It is primarily made of dead, keratinized cells. Each strand of hair is formed in a hair follicle, which is an extension of the epidermis into the dermis.
61
What type of cell responds to light touch?
Meissner corpuscles (tactile corpuscles).
62
What is the typical function of simple cuboidal epithelium?
Secretion and absorption.
63
What is the epiphyseal plate?
It is a layer of hyaline cartilage, found in the metaphysis of a growing bone. The epiphyseal plate is where growth occurs.
64
Which germ layer forms the synovial membranes?
Mesoderm
65
Name the layers of the epidermis, from deep to superficial.
1. Stratum basale.
2. Stratum spinosum.
3. Stratum granulosum.
4. Stratum lucidum (only in hands + feet).
5. Stratum corneum.
66
What are mesenchymal cells?
They are stem cells that give rise to the different types of connective tissue cells.
67
Describe the shape of flat bones.
Thin and curved.
68
What is the function of the stratum basale? How does it accomplish this?
It attaches the epidermis to the dermis (via intertwining collagen fibers).
69
Explain the cellular defect that causes cystic fibrosis.
The gene for a particular Cl– pump, which normally uses ATP to pump Cl– **_down_** its concentration gradient (exception to the rule of ATP pumping **against** the gradient), is mutated. Normally, Cl– is pumped out of the respiratory epithelia, resulting in watery mucus (water follows the Cl–). In people with CF, the mucus is way too thick (cilia cannot operate the mucus elevator).
70
Describe osteocytes.
They are the most abundant bone cell. They are found in lacunae (little spaces) in mature bone. They develop from osteoblasts, after the osteoblast has been trapped by the calcified matrix. They can communicate and receive nutrients through cytoplasmic processes that extend through canaliculi (channels with the bone matrix).
71
Define squamous.
Flattened and thin.
72
Define parenchyma.
The parenchyma is the functional tissue of a gland or organ (as distinguished from the connective and supporting tissue).
73
What is hyaluronan?
It is a compound that is produced by fibroblasts in the synovial membrane. It is released into the joint cavity. It helps trap water and lubricate the joint.
74
Describe elastic cartilage.
It contains elastic fibers, as well as collagen and proteoglycans.
75
Describe the structure of intermediate filaments.
They are composed of keratin.
76
Define trabeculae.
Spikes or sections of the lattice-like matrix in spongy bone. They appear to be random, but each one actually formed along a line of stress, thus strengthening the bone.
77
Name and describe the main types of skin cancer.
Basal cell carcinoma - affects the mitotically active stem cells in the stratum basale.
Squamous cell carcinoma - affects the keratinocytes of the stratum spinosum.
Melanoma - affects the melanocytes (typically develops from a mole). It is the most fatal of all skin cancers, and can metastasize easily. It is difficult to detect before it has spread to other organs.
78
Describe the shape of short bones.
Cube-like.
79
Define canaliculi.
Channels within the bone matrix that house one of an osteocyte’s many cytoplasmic extensions that it uses to communicate and receive nutrients.
80
What is a scar? What type of cell generates scars?
It is a section of collagen-rich skin. The collagen is generated by fibroblasts.
81
Name the two types of bone tissue.
Compact bone, and spongy (cancellous) bone.
82
Name the subdivisions of the posterior cavity.
The cranial cavity and the spinal cavity (these two cavities are continuous with one another).
83
Name the structural protein found in hemidesmosomes.
Integrin.
84
Describe the function(s) of sesamoid bones. Where are they found?
They protect tendons from compressive forces.
They are found in tendons.
Example = patellae.
85
What is eczema? How is it treated?
Eczema is an allergic reaction that manifests as dry, itchy patches of skin that resemble rashes. It can be treated with moisturizers, corticosteroid creams, and immunosuppressants.
86
Describe the structure of cilia.
They consist of microtubules arranged in a "9+2 array" (a ring of 9 microtubule **doublets**, surrounding 2 **single** microtubules in the center).
87
What is the function of adherens junctions?
They help control the shape and folding of the epithelial tissue.
88
Name one possible outcome of frostbite.
Severe frostbite can lead to gangrene, which requires amputation.
89
Which germ layer forms the muscular system?
Mesoderm
90
Which germ layer forms the bladder?
Mesoderm
91
Describe first-degree burns.
It affects **only** the epidermis.
92
What is the difference between yellow marrow and red marrow?
Yellow marrow contains adipose tissue, and is found in the medullary cavity of the diaphysis.
Red marrow contains hematopoietic cells, and is found in the spongy bone in the epiphysis.
93
Define articular cartilage.
A thin layer of cartilage that covers the epiphyses in a joint. It reduces friction.
94
Describe hyaline cartilage.
It is the most common type of cartilage in the body. It consists of short and dispersed collagen fibers, and contains large amounts of proteoglycans.
95
Name 2 substances found in mast cell granules.
Histamine and heparin.
96
Which germ layer forms the GI tract?
Endoderm
97
What type of tissue is blood and lymph classified as?
Liquid connective tissue.
98
Which germ layer forms the adrenal cortex?
Endoderm
99
What is the difference between serous glands and mucous glands?
Serous glands produce watery plasma-like secretions. Mucous glands produce thicker secretions that are rich in the glycoprotein known as mucin.
100
Name the 2 major forms of supportive connective tissue.
Bones and cartilage.
101
Which germ layer forms the circulatory system?
Mesoderm
102
Which germ layer forms the epithelia of the lungs?
Endoderm
103
Explain how CT scans work. What are they used for? What are the advantages and drawbacks?
CT = computerized tomography. A patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360° around the patient, taking X-ray images. A computer combines these images into a 2D "slice". Advantages: good for soft-tissue scanning, forms very precise images. Drawbacks: patients are exposed to a huge dose of radiation.
104
Name the main subdivisions of the anterior cavity.
The thoracic cavity and the abdominopelvic cavity.
105
Name the 4 types of cells found in bone tissue.
Osteoblasts, osteocytes, osteogenic cells, and osteoclasts.
106
Describe the stratum corneum.
It is the most superficial layer of the epidermis. This layer is dry and dead. It protects against microbes, mechanical abrasion, and dehydration.
107
How did the stratum granulosum get its name? Describe it.
This layer has a grainy appearance, because the keratinocytes start to generate lots of keratin (fibrous) and keratohyalin (accumulates in granules).
108
Define articulation.
A place where two bone surfaces come together.
109
What happens when a person doesn't get enough vitamin D?
The disease called rickets may develop. This is a disease in children that causes them to have misshapen bones.
110
Which germ layer forms the outer layers of the skin?
Ectoderm
111
Describe spongy bone.
In this type of bone, the osteocytes are NOT arranged in concentric circles. Instead, they are found in a network of matrix spikes called trabeculae. The spaces in the trabeculated network help make bones lighter, and also sometimes contain red marrow.
112
Describe the general process of hair growth (not the phases). How does it work?
It begins with the production of keratinocytes by the basal cells of the hair bulb. As new cells are created, the hair shaft is pushed upward. Keratinization is completed as the cells die and are pushed outside. The visible portion of the hair is completely dead and composed entirely of keratin.
113
In the cytoskeleton, what type of force do intermediate filaments resist?
Tension.
114
Describe the abdominopelvic cavity.
It is the inferior subdivision of the anterior cavity. It is the largest cavity in the body. It contains the digestive organs (abdominal cavity) and the reproductive organs (pelvic cavity). There is no physical membrane that divides the abdominal cavity from the pelvic cavity.
115
In the cytoskeleton, what type of force do microtubules resist?
Compression.
116
What is the proper term for sweat glands?
Sudoriferous glands.
117
Describe fibrocartilage.
It has thick bundles of collagen fibers, so it is very tough.
118
Describe the shape of irregular bones.
They have a complex shape.
119
What happens to the melanin that is produced by melanocytes?
It is transferred to the keratinocytes via cellular vesicles called melanosomes.
120
Name the type of cell that forms cartilage. How do they do this? What compound do they secrete?
Chondrocytes secrete chondroitin sulfates (polysaccharides), which combine with ground substance proteins to form proteoglycans.
121
Describe the shape of long bones.
Cylindrical.
122
What are Meissner corpuscles? Where are they found?
They are touch receptors found in the papillary layer of the dermis.
123
Which germ layer forms the adrenal medulla?
Ectoderm
124
Describe the 3 different classes of exocrine glands found in the body.
Merocrine = contents are released by exocytosis.
Apocrine = a portion of the cell is pinched off.
Holocrine = the mature cell dies and ruptures, releasing its contents.
125
Name the structural proteins found in adherens junctions.
They use either cadherins or integrins. They also have actin on the cytoplasmic side. The actin helps give shape to the epithelial tissue.
126
What are melanocytes? What do they do? Where are they found?
Melanocytes produce melanin. They are found in the stratum basale.
127
Does adipose tissue have a good supply of capillaries? Why or why not?
Yes, because this allows them to rapidly store or release lipids.
128
Explain how PET scans work. What are they used for? What are the advantages and drawbacks?
Positron emission tomography (PET) uses radiopharmaceuticals (substances that emit radiation that is short-lived, and therefore relatively safe for use in the body) to generate an image of physiological activity, including nutrient metabolism and blood flow. Metabolically active areas appear as "hot spots". It is used for a wide variety of diagnostic purposes. Advantage: can image the body in real-time (not static like CT and MRI). Drawbacks: high cost, and exposes patients to some radiation.
129
Which germ layer forms connective tissue?
Mesoderm.
130
Describe reticular tissue.
It is a mesh-like, supportive framework for soft organs (examples: lymphatic tissue, spleen, liver).
131
How did the stratum spinosum get its name? Describe it.
The cells in this layer appear spiny, due to their desmosomes.
132
Define columnar.
Taller than it is wide.
133
Describe the composition of epithelial membranes.
They are composed of an epithelial layer attached to layer of connective tissue.
134
What does fMRI stand for? What can it detect, and what is it used for?
Functional magnetic resonance imaging. It can detect the concentration of blood flow in certain body parts. It is used to study the activity of different brain regions.
135
What is cyanosis? Why does this particular color become visible?
A sudden drop in oxygenation can cause the skin to turn pale initially. Prolonged oxygen deprivation will cause dark red deoxyhemoglobin to predominate, which makes the skin appear blue (cyanosis).
136
What is the proper term for bedsores? What is the cause of them? What is the ultimate result of them?
Decubitis ulcers. They are caused by prolonged lack of blood flow to a region, resulting in necrosis. Bedsores can be fatal if they become infected.
137
How many serous cavities are found in the body? Name them. What is the purpose of their membranes?
There are 3 serous cavities in the body (pleura, pericardium, and peritoneum). The serous membranes form fluid-filled sacs that cushion the internal organs, and reduce friction (too much friction could lead to inflammation).
138
Describe the general structure of sweat glands. What "class" of gland are they?
Sweat glands develop from epidermal cells which project into the dermis. Most are merocrine glands, but some are apocrine glands.
139
Define glycocalyx.
The glycocalyx is a glycoprotein and glycolipid covering found outside the PM of most epithelial cells.
140
What are the two largest compartments of the body?
The posterior (dorsal) cavity and the anterior (ventral) cavity.
141
Define cuboidal.
Box-shaped, like a cube.
142
What are the 2 parts of a long bone? Briefly describe each one. At what structure do they meet?
The diaphysis is the long, narrow part of a long bone. Its walls are composed of compact bone. Inside, it has a hollow region called the medullary cavity, which contains yellow marrow.
The epiphysis is the wider section at each end of a long bone. It is filled with spongy bone, with red marrow in the spaces.
They meet at the metaphysis.
143
Which germ layer forms the sweat glands?
Ectoderm
144
Describe the function(s) of long bones. Where are they found?
They function as levers (they move when muscles contract).
They are found in the arms, legs, fingers, and toes.
145
What is a serosa? Describe it in detail.
It is another name for a serous membrane. It is a thin membrane that covers the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers line the walls of the cavity, and the visceral layers cover the organs. Between these two layers, there is a very thin fluid-filled space.
146
What is the difference between tubular glands, alveolar glands, and tubuloalveolar glands?
Tubular glands have straight or coiled ducts. Alveolar glands have ducts that form little pockets. Tubuloalveolar glands have a combination of both.
147
Define primary union and secondary union.
Primary union = the healing of a wound when the edges are close together.
Secondary union = the edges of a gaping wound are pulled together by refilling of the wound with cells and collagen (in a process called wound contraction).
For wounds deeper than ¼ inch, sutures are recommended in order to promote a primary union and avoid scarring.
148
Which germ layer forms the nervous system?
Ectoderm
149
Define caudal.
Caudal is another term for inferior. It describes a position below or lower than another part of the body.
150
Explain how inorganic salt crystals help form the structure of bone.
When calcium phosphate and calcium carbonate combine in the collagen matrix, they form hydroxyapatite. This mineral is responsible for the hardness and strength of bones.
151
Which germ layer forms the pancreas?
Endoderm
152
Describe the structure of flagella.
They consist of microtubules arranged in a "9+2 array" (a ring of 9 microtubule **doublets**, surrounding 2 **single** microtubules in the center).
153
Define peritoneum.
It is the serous membrane that lines the abdominopelvic cavity and covers the organs found there.
154
What is a sebacious gland?
It is a type of oil gland that secretes sebum (a mixture of lipids). It helps to lubricate and waterproof the skin and hair.
155
What is the difference between simple glands and compound glands?
In a simple gland, the duct is single. In a compound gland, the duct is divided into branches.
156
What is the sagittal plane?
It is the plane that divides the body vertically into left and right halves.
157
What gives hair its color?
Several different types of melanin.
158
Which germ layer forms the inner layers of the skin?
Mesoderm
159
What are the two basic types of tissue membranes?
Connective tissue and epithelial membranes.
160
What happens to the skin when it is burned?
The skin cells die, which can lead to a massive loss of fluid. The risk of infection is very high.
161
Describe osteoclasts.
They are responsible for bone resorption (breakdown). They originate from monocytes and macrophages.
162
Define goblet cell.
It is a unicellular "gland" that secretes mucous. They are found in mucous membranes.
163
Which germ layer forms the inner layers of the lungs?
Endoderm
164
Describe perforating canals.
They are also known as Volkmann's canals. They are channels that branch off from the central canal at right angles. They extend to the periosteum and endosteum.
165
Which layers of the epidermis do and do not contain keratinocytes?
The stratum basale does not, but all the rest of the layers are composed of keratinocytes.
166
What is the basement membrane?
It is the extra-cellular matrix that separates the epithelium from the underlying connective tissue. It is composed of two layers: the basal lamina, and the underlying reticular lamina.
167
Name the types of cells found in the stratum basale.
Basal cells, Merkel cells, and melanocytes.
168
Name the cells and structures that are found in the papillary layer of the dermis.
Fibroblasts, adipocytes, small blood vessels, phagocytes, lymphatic capillaries, nerve fibers, and Meissner corpuscles.
169
In which layer of the skin is most "extra" fat stored by obese people?
The hypodermis.
170
Explain how MRI scans work. What are they used for? What are the advantages and drawbacks?
Magnetic resonance imaging is based on the fact that matter exposed to magnetic fields and radio waves will emit radio signals. MRI can be used to locate tumors. Advantages: very precise, and patients are NOT exposed to radiation. Drawbacks: High cost, and patient discomfort during the loud, scary procedure.
171
What is the medullary cavity?
It is the hollow region of the diaphysis. It is filled with yellow marrow.
172
What role does actin play in cell division?
Together with myosin, it forms the cleavage furrow and causes cytokinesis.
173
Which germ layer forms the liver?
Endoderm
174
Describe osteogenic cells.
They are the only bone cells that divide. They differentiate and develop into osteoblasts, in order to replace old bone cells that have died.
175
Define transitional epithelium.
This is a special kind of epithelium found in the urinary bladder. It is able to change shape as the bladder fills.
176
Describe the reticular layer of the dermis.
It is composed of dense, irregular connective tissue (elastin and collagen).
177
Define endosteum.
It is the inner lining of the medullary cavity. It is where bone growth, repair, and remodeling occur.
178
Describe the thoracic cavity.
It is the superior subdivision of the anterior cavity. It is enclosed by the rib cage. It contains the lungs and the heart.
179
Define pericardium.
It is the serous membrane that surrounds the heart in the pericardial cavity.
180
Which germ layer forms the ovaries?
Mesoderm
181
Describe the shape of sesamoid bones.
Small and round (like a sesame seed).
182
Describe osteoblasts. What eventually happens to them?
Their function is to form new bone. They secrete the collagen matrix and calcium salts. As the surrounding matrix calcifies, the osteoblasts get stuck, causing them to become osteocytes.
183
Explain "controlled hypothermia".
In a clinical setting, hypothermia is sometimes induced (for example, during open-heart surgery or to treat cardiac arrest).
184
How did the stratum lucidum get its name? Describe it.
This layer is found only in the "thick skin" of the palms and feet. The cells in this layer are dead and flattened. They are packed with eleidin, which gives them their translucent appearance and provides a barrier to water.
185
What is a corn? How does it form?
A corn is a specialized form of callus. It forms from abrasions that occur in an elliptical-type motion.
186
Describe osteons.
They are the functional unit of compact bone. Each osteon is composed of concentric rings of calcified matrix called lamellae. Each osteon has a central canal (Haversian canal) running down its center.
187
What are Langerhans cells? What do they do? Where are they found?
Langerhans cells are dendritic cells that are found in the stratum spinosum. They engulf foreign particles and damaged cells.
188
What structure separates the subdivisions of the anterior cavity?
The diaphragm.
189
Which germ layer forms the testes?
Mesoderm
190
What happens to the epiphyseal plate after growth stops?
The hyaline cartilage is replaced by osseous tissue, and the epiphyseal plate becomes an epiphyseal line.
191
What are Merkel cells? What do they do? Where are they found?
Merkel cells act as receptors that stimulate sensory nerves in response to touch. They are found in the stratum basale (extra in the hands + feet).
192
What is keratohyalin? What does it do? Where is it found?
It is a protein that accumulates in the granules of the cells in the stratum granulosum. When the cell gets pushed up to the next layer, it will form eleiden.
193
What type of tissue forms the connective tissue part of the arterial walls?
Dense irregular elastic tissue.
194
What is the lamina propria?
It is a thin layer of areolar connective tissue, found under the epithelium. It is found in mucous membranes.
195
Define nutrient foramen.
A small opening in the compact bone tissue of the diaphysis, that allows arteries to enter the bone and provide nourishment.
196
Name and briefly describe the 3 main types of fibers that are secreted by fibroblasts.
1. Collagen fiber = made from fibrous protein subunits linked to form a long straight fiber.
2. Elastic fiber = contains elastin, and will return to its original shape after being moved.
3. Reticular fiber = formed from the same subunits as collagen fibers, but remain narrow and are arrayed in a branching network.
197
Describe the structure of nails, and how they are formed.
The nail body is composed of densely packed dead keratinocytes. The nail body is formed from continuously-growing cells in a specialized structure derived from the stratum basale.
198
Give the alternate definition of the word "cranial" (not necessarily relating to the skull).
Cranial is another term for superior.
199
Describe second-degree burns.
It affects the epidermis, and part of the dermis. It results in swelling and painful blistering. It is important to keep the burn site clean and sterile.
200
Which germ layer forms the hair?
Ectoderm
201
What is the frontal plane?
It is the plane that divides the body into anterior and posterior halves.
202
What type of tissue are tendons and ligaments made of? Be specific.
Dense regular connective tissue.
203
What is the most abundant cell type in connective tissue proper? What do they do?
Fibroblasts. They secrete proteins and polysaccharides, which combine with extra-cellular fluids to form a viscous ground substance, that forms the ECM along with fibrous proteins.
204
Describe central canals.
They are also known as Haversian canals. One can be found at the center of each osteon. They contain blood vessels, lymph vessels, and nerves.
205
Describe the four quadrant system.
It is used to divide the abdomen into four quadrants, which all intersect at the navel. The quadrants are named as follows (in no particular order):
Right upper quadrant, Left upper quadrant, Right lower quadrant, and Left lower quadrant.
206
Does cartilaginous tissue have a good supply of capillaries? Why or why not?
No (not sure why not).
207
What is one benefit of melanin, besides protecting DNA from UV rays?
It protects folic acid from destruction by UV rays.
208
Describe the function(s) of irregular bones. Where are they found?
They protect internal organs.
Examples = vertebrae, and facial bones.
209
What are the phases of hair growth? What happens in each phase, and how long does each phase last?
1. Anagen phase (2-7 years) - Cells divide rapidly at the root, and push the hair up.
2. Catagen phase (2-3 weeks) - Transition from active growth to rest.
3. Telogen phase (2-4 months) - Hair follicle is at rest and no new growth occurs. After this phase is over, a new anagen phase starts and the old hair is pushed out and falls off.
210
Define lacunae.
The spaces occupied by chondrocytes, within the cartilage matrix.
211
What are mesenchymal cells?
They are multipotent adult stem cells that can differentiate into any type of connective tissue cell.
