Set 1 Flashcards
1
Q
What is physiology?
A
The study of the normal functioning of a living organism and its component parts
2
Q
What are the six levels of organization within the body?
A
- Molecules
- Cells
- Tissue
- Organs
- Organ Systems
- Organism
3
Q
What are emergent properties?
A
Complex functions that cannot be predicted from the properties of the individual component parts
4
Q
What are the 10 physiological organ systems?
A
- Integumentary
- Musculoskeletal
- Respiratory
- Digestive
- Urinary
- Immune
- Circulatory
- Nervous
- Endocrine
- Reproductive
5
Q
Differentiate function and mechanism.
A
- Function is “why” (teleological)
- Mechanism is “how” (mechanistic)
6
Q
What is homeostasis?
A
Maintenance of a relatively constant internal environment (input = output)
7
Q
What does the failure to maintain homeostasis result in?
A
Illness or disease
8
Q
What is the body’s internal environment?
A
Extracellular fluid
9
Q
In the body, what is input? What is output? Which law does this reflect?
A
- Input: metabolism or outside environment (food)
- Output: metabolism or excretion
- Law of mass balance (input = output)
10
Q
What is clearance? Which organs are responsible for clearance?
A
- The rate at which a material is removed from the blood by excretion, metabolism, or both
- Liver, kidneys, lungs, skin
11
Q
Is steady state the same as equilibrium?
A
- No, steady state is dynamic, whereas equilibrium implies compositions are identical
- Homeostasis is a dynamic steady state
12
Q
How are regulated variables maintained?
A
- They have a setpoint and a normal range
- If deviations occur, homeostatic mechanisms are set in place
13
Q
Define local control.
A
- Simple form of control
- Restricted to the tissue or cell involved
- Ex: Blood vessels dilate when oxygen in a tissue decreases
14
Q
What are the components of a simple control system?
A
- Input signal
- Integrating center
- Output signal
- Response
15
Q
What are the three components of control systems?
A
- Input signal
- Integrating center
- Output signal
16
Q
What are the reflex steps of a response loop?
A
- Stimulus
- Sensor
- Input signal
- Integrating center
- Output signal
- Target
- Response
17
Q
What monitors the variable in a response loop?
A
Sensor
18
Q
What modulates response loops?
A
Feedback loops
19
Q
What is a negative feedback loop?
A
Response opposes or removes the original stimulus, which in turn stops the response loop
20
Q
What is a positive feedback loop?
A
- Response reinforces the stimulus rather than decreasing or removing it
- Destabilizes the system until some intervention occurs to stop the loop
21
Q
What is feedforward control?
A
Allows the body to predict that a change is about to occur and start the response loop in anticipation of the change
22
Q
What are biological rhythms?
A
Regulated variables that change in a predictable manner
23
Q
What are circadian rhythms?
A
Biological rhythms that coincide with light-dark cycles
24
Q
Differentiate the independent and dependent variable.
A
- Independent: factor manipulated by the investigator
- Dependent: observed factor
25
What is a crossover study?
The control group in the first half of the experiment becomes the experimental group in the second half
26
Name four major themes in physiology.
- Structure/function relationships
- Biological energy use
- Information flow within the body
- Homeostasis
27
Which systems exchange with the outside environment?
- Respiratory (gases)
- Digestive (nutrients)
- Digestive and urinary (waste products)
- Integumentary (water and solute losses)
28
What does the darker region in the nucleus correspond to?
- Heterochromatin (DNA wound with histones H2A, H2B, H3, H4)
| - Genes are not expressed since they are not needed in that cell type
29
What does the lighter region in the nucleus correspond to?
- Euchromatin (DNA without histones)
| - Genes that are actively expressed
30
What are retrotransposons? Where are they contained?
- Genetic sequence that shows homology with a virus, interlopers in our genome
- Contained in heterochromatin to prevent expression
31
What is small, non-coding RNA?
- Also transcribed
- Is complimentary to mRNA, and can cause it to be degraded
- It is a silencing RNA
32
What is the function of the Golgi apparatus?
- Connection of canals
| - Proteins that are destined for vesicles are modified in the Golgi
33
What are lysosomes?
Involved in the destruction of things that the cell does not need anymore
34
Epithelial cells are polarized. What does that mean?
- When you have a surface that is different from another
| - Apical surface
35
In a secretory epithelial cell, which surface secretes into the lumen?
Apical surface
36
What does an epithelial cell sit on?
- Basement membrane (extracellular matrix), which is laminin rich
- Epithelium lies over connective tissue composed of fibroblast/stromal cells
37
What makes a cell specialized?
- Control of gene expression
| - Unique cell-specific transcriptomes and proteomes
38
All cells have the same DNA. Why are cells specialized then?
The compartmentalization into heterochromatin and euchromatin allows the cell to decide which genes to actively transcribe and express
39
Scientists are now capable to sequence the entire transcriptome and proteome of a single cell. Why is this necessary?
- To know what's normal
- To know what happens when things go wrong
- To be able to compare the two, so you can identify target drugs
- Personalized pharmaceutical approach (i.e. cancer)
40
What are the four factors that are essential for cell differentiation?
1. Cell-cell communication
2. Growth factors
3. Extracellular matrix composition
4. Cell location in a differentiating embryo
41
Which cells are induced to become differentiated cells?
Stem cells
42
Where can we acquire stem cells?
- Umbilical cords, embryos
| - Now, bone, brain, and gut (can't form any cell type, but retain plasticity)
43
Which cells give rise to the placenta? What are they?
- Trophoblast cells
| - Outer layer of a blastocyst
44
During the blastocyst stage, embryonic stem cells are said to be _________. Why?
- Totipotent
| - Because they can give rise to any cell type in the body
45
Gastrulation gives rise to the primary germ layers. What are the three?
- Endoderm
- Mesoderm
- Ectoderm
46
What tissues does the endoderm give rise to?
- Lung
- Pancreas
- Liver
- GI tract
- Urogenital tract
- Endocrine glands
47
What tissues does the mesoderm give rise to?
- Kidney
- Bone
- Heart
48
What tissues does the ectoderm give rise to?
- Eye
- Nervous system
- Skin
- Endocrine glands
49
What are the four major tissue types?
- Epithelial
- Connective tissue
- Muscle
- Nervous
50
How do histologists prepare slides?
- Fix the tissue with paraformaldehyde
- Embedded in wax (paraffin)
- Cut into micrometer sections
- Placed on a slide, remove wax, staining
51
What is the H&E stain?
- Hematoxylin and eosin stain
- H stains nuclei purple
- E stains intracellular and extracellular
52
What are the characteristics of epithal tissue?
- One or more layers of densely arranged cells
| - Very LITTLE extracellular matrix
53
What are the three functions of epithelial tissue?
1) Covers and protects the body surfaces (sheets)
2) Lines body cavities
3) Movement of substances, glandular activity (secretory)
54
Where is epithelial tissue found?
- Skin
- Lining of respiratory tract
- Digestive tract
- Urinary
- Glands of the body
55
Why is there more connective tissue in the uterus than in the trachea?
Because the uterus needs to stretch more to accomodate for a growing fetus
56
What are the characteristics of connective tissue?
- Few cells
| - LOTS of extracellular matrix
57
True or False: all connective tissue cells (fibroblasts) secrete ECM molecules (ex: collagen) to give support and form to structures.
False, all connective tissue cells EXCEPT for blood cells
58
What are the functions of connective tissue?
- Connects, anchors, and supports body structures
- Transport
- Provides structural and metabolic support
59
Name six types of connective tissues.
- Bone
- Cartilage
- Blood
- Adipose
- Loose connective tissue proper
- Dense connective tissue proper
60
What determines the properties of the connective tissue?
- Variations in the composition of the extracellular matrix
| - Ex: if matrix is calcified, it forms bone or teeth
61
What is the extracellular matrix of connective tissue made of?
- Glycoproteins
- Fibrous proteins
- Glycosoaminoglycans
62
How can you differentiate smooth muscle from skeletal muscle and cardiac muscle?
Smooth muscle does not possess striations
63
Where is smooth muscle found?
Surrounding hollow organs (stomach, bladder, uterus)
64
Where is nervous tissue found?
- Brain
- Spinal cord
- Nerves
65
How do different tissues function to support the stomach?
- Smooth muscle: contraction of the stomach
- Nervous tissue: stimulates stomach to secrete gastric juices
- Loose connective tissue: support and structure
- Columnar epithelium: produce and secrete enzymes, gastric juices, mucus
- Blood: hormones, nutrients, waste
66
What is intracellular control?
- Operates within cells
| - Genes or enzymes often regulate cell processes
67
What is intrinsic control?
- Autoregulation
- Regulation within tissues or organs
- May involve chemical signals (Ex: growth factors in ovary)
68
What is extrinsic control?
- Regulation from organ to organ
- May involve nerve signals
- May involve endocrine signals (hormones)
69
Which of the following is NOT an example of a homeostatic response:
1. Body temperature increases, and sweating brings the body temperature down.
2. The oxygen level in the blood falls, and breathing harder increases the oxygen level in the blood.
3. Sweating leads to loss of body fluids, and urination increases the loss of body fluids.
4. Glucose level in the blood falls, and eating increases the glucose level in the blood.
3. Sweating leads to loss of body fluids, and urination increases the loss of body fluids.
70
The following concept is an example of which level of control:
Estrogen from the ovary binds to the estrogen receptor, which turns on specific genes that drive the cells to produce specific substances and undergo mitosis.
Intracellular
71
The following concept is an example of which level of control:
Epithelial cells lining the uterus communicate with each other by producing extracellular matrix factors, which lead to the production of different growth factors that are required to support a pregnancy, should there be one.
Intrinsic
72
The following concept is an example of which level of control:
- Brain releases GNRH, pituitary releases FSH
- FSH stimulates ovarian gland to produce estrogen
- Estrogen causes epithelial cells to proliferate and secrete substances to support pregnancy.
Extrinsic
73
Which tissues are avascular?
- Epithelium
| - Cartilage (connective tissue)
74
What are fibroblasts?
Cells that secrete matrix proteins
75
What is ground substance?
Matrix of the loose connective tissue
76
What is the ground substance, fiber type and arrangement, main cell types of loose connective tissue?
- Ground substance: gel (more ground than fibers and cells)
- Fiber type: collagen, elastic, reticular
- Main cells: fibroblasts
77
Where is loose connective tissue found?
- Sin
- Around blood vessels and organs
- Under epithelia
78
What is the ground substance, fiber type and arrangement, main cell types of dense connective tissue?
- Ground substance: more fibers than ground
- Fiber type: mostly collagen
- Main cells: fibroblasts
79
Where is dense irregular connective tissue found? Where is dense regular connective tissue found?
- Irregular: muscle and nerve sheaths
| - Regular: tendons and ligaments
80
What is the ground substance, fiber type and arrangement, main cell types of cartilage?
- Ground substance: firm but flexible
- Fiber type: collagen
- Main cells: chondroblasts
81
Differentiate white and brown fat.
- White: single lipid droplet
| - Brown: multiple lipid droplets
82
What do lipid droplets influence in adipose cells?
Displace cytosol
83
Compare cartilage and bone. How good are they at regeneration?
- Cartilage: very poor at regenerating (no blood supply); light and flexible
- Bone: very good at regenerating; calcified and rigid
84
What are fixed connective tissue cells?
- Macrophages
- Adipocytes
- Fibroblasts
85
What are the two characteristics of muscle tissues?
- Contractile (force and movement)
| - Signal transduction
86
What are the striations in skeletal muscle? Is it under voluntary or involuntary control?
- Striations are actin and myosin filaments
| - Voluntary control
87
What is an intercalated disc composed of? What are their functions?
- Desmosome: links cells together
| - Gap junction: permits communication between cells by linking cytoplasms together
88
How many nuclei do cardiac and smooth muscle cells possess? Are they under voluntary or involuntary control?
- Cardiac: normally one (involuntary control)
| - Smooth: one (involuntary control)
89
What signals do neurons send?
- Excitable
- Electrical
- Chemical
90
Describe the functions of dendrites, cell body, and axon in a neuron.
- Dendrites: input signal
- Cell body: integration center
- Axon: output signal
91
How does cell differentiation occur?
- Through the control of gene expression
| - Chemical signals are being released from cells, which tell other cells how to differentiate
92
In an embryo (blastocyst), cells are not yet differentiated, and they are called _______.
totipotent
93
What are totipotent cells?
- Can divide and produce all of the differentiated cells in an organism
- May develop any fate that they want, usually based on their environment during differentiation
94
Stem cells in adults are _______potent cells. What does this mean?
- pluripotent
- Can't become absolutely anything, but are still flexible. They require some guidance through genes to reach their final fate
95
Where in the body can you find adult stem cells?
- Embryo
- Bone marrow
- Epithelial layers can be regenerated
96
Which gonads possess stem cells?
- Testes: in the spermatogonia
| - Ovary: NONE
97
Which tissue possesses a small population of stem cells that are difficult to regenerate?
Neural and muscle
98
Stem cells hold great promise for medical therapies for two reasons, what are they?
1) Undifferentiated cells give rise to almost or any cell type
2) Highly proliferative: large quantities can be produced for medical purposes, such as repairing damaged tissue
99
What diseases and injuries are currently being explored with stem cell therapy?
- Spinal cord injury
- Cardiovascular disease
- Alzheimer's
100
How can we get stem cells for research and treatments through in vitro fertilization?
- Egg and sperm fertilize (zygote formatoin)
- Formation of the blastocyst
- Cells are taken from the inner cell mast
- Harvest and culture
- Brand-new embryonic stem cells
101
How can we get stem cells for research and treatments by nuclear transplantation?
- Enucleated somatic diploid cell
- Somatic cell nuclear transfer
- Zygote, cell division, blastocyst
- Harvest and culture
102
Explain the therapeutic cloning to isolate stem cells in patients with degenerating nerve diseases (e.g. Lou Gehrigs).
- Harvest somatic cell, place in donor meiosis II oocyte
- Mature to blastocyst and harvest
- Treat in vivo with a chemical cocktail to get cells to differentiate into the appropriate cell type
- Transplant back to patient
103
What is the difficulty of isolating stem cells using therapeutic cloning?
Getting the cells to differentiate into the appropriate cell type
104
What is the danger of therapeutic cloning to isolate stem cells? What is an advantage?
- Danger: cancer (undifferentiated cells may easily become cancerous)
- Advantage: you may treat patients with a tissue that is a perfect match for them
105
What are alternative sources of stem cells?
- Adult bone marrow
| - Testis stem cells (not necessarily able to make all cell/tissue types)
106
Explain the study that demonstrated the potential for patients to provide their own stem cells.
- Induced pluripotent stem cells created by forced expression of four transcription factors in mouse fibroblasts
- Fibroblasts were reverted to a stem-cell like state
- These cells were then implanted into an embryo and produced viable mice
107
What was Project RESTORE?
- Great leaps in spinal cord restoration using stem cell therapy in rats
- Embryonic stem cells were injected into rat spinal cord fluid who model nerve disease
- Stem cells did not regrow but restored the environment to prevent further damage
108
What are the four major structures of all eukaryotic cells?
- Plasma membrane
- Cytoplasm
- Nucleus
- Organelles
109
Differentiate the plasma and organelle membrane.
- Plasma: encloses the cell
| - Organelle: sacs and canals made of the same material as the plasma membrane that enclose organelles
110
Describe the plasma membrane structure.
- Lipid bilayer of phospholipid molecules
| - Hydrophobic; water or water-soluble molecules do not pass through easily
111
What are the functions of membranes?
1) Control transport
2) Allow selective receptivity and signalling via transmembrane receptors
3) Surface glycoproteins (immune)
4) Anchor for cytoskeleton or ECM
5) Provides sites for the binding and catalysis of enzymes
6) Passageway across membrane for certain molecules (ex: gap junctions)
112
What are self-markers?
- MHC
- Molecules on the surface of human cells that are unique to an individual
- Identifies the cells as "self" to the immune system
113
What is self-tolerance?
The ability of our immune system to attack abnormal or foreign cells, but spare our own normal cells
114
What are non-self markers?
Molecules on the surface of foreign or abnormal cells or particles act as flags to the immune system as "non-self"
115
What is the function of a protein channel in a cell membrane? Give an example.
- Controlled transport of water-soluble molecules
- Movement of sodium and potassium
- Urinary system (important for regulating water)
116
What gives the specificity of protein channels?
- Given by recognition of the shape of the molecule
| - Can open or close gated channels
117
Describe what happens in dehydration or increased salt consumption.
1) Osmoreceptor cells in the hypothalamus detect an increase in the osmolarity of blood
2) Hypothalamus signals the pituitary to release ADH
3) ADH acts on the distal tubule of the kidney to increase water permeability by inserting aquaporin channels
4) Water moves out of the distal convoluted tubule by osmosis (decreases osmolarity)
5) Increased water reabsorption by the kidney and a decrease in urine flow
118
What is the function of a membrane receptor? Give an example.
- Triggers an intracellular signalling cascade that will alter intracellular activities when bound by a ligand
- Ex: FSH hormone receptor
119
Describe the G protein cascade. What is it an example of?
- Membrane receptor
- Binding of ligand to G proteins causes ATP conversion to cAMP
- cAMP is the secondary messenger that activates PKA
120
What are the functions of integral membrane proteins?
- Binds other integral membrane proteins to form cell-cell connections
- Binds ECM to give structure to tissues
121
What are integrins? What are their functions?
- Integral proteins (structural adhesion proteins)
- Cell adhesion (cell-cell or cell-ECM)
- Involved in wound healing, angiogenesis, development, embryo attachment, cancer invasion
122
What did Dr. Kimmins' research concerning integrins and embryo attachment?
- Integrin alpha6 is involved in embryo attachment to the uterus
- Integrin alpha V beta 3 was not involved
123
What is the cytoplasm? How does it relate to cytosol?
- Gel-like internal substance of cells that includes many organelles
- Suspended in watery intracellular fluid called cytosol
124
Differentiate membranous and non-membranous organelles.
- Membranous: specialized sacs or canals made of cell membranes (Golgi, ER, plasma membrane, lysosomes, proteosomes)
- Non-membranes: microscopic filaments or other non-membranous materials (cytoskeleton, ribosomes, cilia, flagella, nucleolus)
125
What is the structure of the ER?
- Made of canals with membranous walls present throughout the cytoplasm
- Extends from the nucleus to the plasma membrane
126
What is the function of the ER?
- Protein transport from the nucleus, to the cytoplasm, to the cell surface for release
- Proteins move through the canals
127
What is the structure and function of the rough endoplasmic reticulum?
- Ribosomes are found on the outer surface of the wall
- Ribosomes synthesize proteins
- Transports proteins to Golgi
128
What is the structure and function of the smooth endoplasmic reticulum?
- Does not have ribosomes on the wall
| - Synthesizes certain lipids and carbohydrates
129
What function of the smooth endoplasmic reticulum is important for muscle contraction and hormone production?
Removes and stores calcium from the cell's interior
130
Are ribosomes membranous or non-membranous? What are they made of?
- Non-membranous
| - Two pieces (large and small subunit); composed of ribosomal RNA
131
Differentiate free ribosomes and ribosomes that are attached to the ER.
- Free ribosomes: proteins for the cell's domestic use
| - ER ribosomes: proteins for export
132
Working ribosomes form groups known as ________.
polyribosomes
133
Describe the structure of the Golgi.
- Membranous organelle consisting of cisternae stacked on one another
- Located near the nucleus
134
What are the functions of the Golgi?
- Processes and packages protein molecules from the ER
| - Modified by enzymes residing in the Golgi
135
How do processed proteins leave the final cisternae of the Golgi?
- In a vesicle
| - Contents may then be secreted to outside the cell (by fusing with plasma membrane)
136
Describe the structure of lysosomes.
Made of microscopic membranous sacs that have "pinched off" from the Golgi apparatus
137
What are the functions of lysosomes?
- Cell digestion/recycling system performed by enzymes
- Breaks down proteins, food molecules, foreign particles (neutrophils), such as bacteria, old organelles
- Amino acids are recycled
138
What is Tay-Sachs disease?
- Caused by a failure to produce an enzyme needed to break down lipids-gangliosides (fatty acid derivatives found in all cell membranes)
- Hexoaminidase A (enzyme)
- Accumulation of gangliosides, which are toxic to the cell, causes cell death
- Individuals only live to 5-6 years old; child loses vision because of accumulation in the retina of gangliosides
139
What is the proteosome's function?
- Break down protein molecules one at a time by tagging each one with a chain of ubiquintin molecules and unfolding it as it enters the proteosome, then breaking apart peptide bonds
- Short peptide chains exit the other end of the proteosome
140
Describe the link between proteosomes and Parkinson's disease.
- The proteosome system fails and improperly folded proteins kill nerve cells in the brain that regulate muscle tension
- Damage in the brain to the substantia nigra, which is responsible for secreting dopamine
141
Describe the structure of the mitochondria. Where are enzymes located?
- Inner and outer membranes separated by fluid
| - Enzymes are attached to both membranes
142
What is the function of the mitochondria?
- Power plants of cells
| - Mitochondrial enzymes catalyze a series of oxidation reactions that provide about 95% of the cell's energy supply
143
What kind of DNA does each mitochondria possess? Which parent is it inherited from?
- Single circular DNA, allowing it to produce its own enzymes and replicate copies of itself
- Only inherited from mother (involved in Parkinson, Alzheimer, and Diabetes inheritance)
144
Describe the structure of the nucleus.
- Consists of a nuclear envelope (composed of two membranes) surrounding nucleoplasm
- Nuclear envelope has nuclear pores
145
How many nuclei do regular cells possess?
- Normally, single nucleus
- Cancer cells: multinucleated
- Skeletal muscle: multinucleated
146
What is the function of nuclear pores in the nuclear envelope?
Allow mRNA, proteins, such as transcription factors, in and out of the nucleus
147
Differentiate heterochromatin and euchromatin.
- Heterochromatin: silent genes, tightly compacted
| - Euchromatin: active sites of gene expression/transcription
148
What is a nucleosome?
- Basic unit of DNA packaging in eukaryotes
| - Consists of a segment of DNA wound in sequence around 8 histone protein cores (H2A, H2AC, H2B, H3, H4)
149
Describe the structure of the cytoskeleton.
Internal supporting framework made up of rigid, rod-like pieces
150
What are the functions of the cytoskeleton?
- Provides support
- Allows movement of cells and of proteins and organelles within the cell
- Serves critical functions in chromatin movement and mechanisms during mitosis and meiosis
151
What are the smallest cell fibers in the cytoskeleton called? What are they made of?
- Microfilaments
| - Thin, twisted strands of protein molecules that lie parallel to the long axis of the cell
152
What is the function of microfilaments?
Can slide past each other, causing shortening of cell-muscle contraction
153
Describe the sliding filament model.
1) ATP binds to myosin
2) Myosin hydrolyzes ATP (energy from ATP rotates the myosin head, which binds weakly to actin)
3) Pulls the thin filaments past the thick
154
What are intermediate filaments? What do they form?
- Twisted protein strands slightly thicker than microfilaments
- Form much of the supporting framework in many types of cells
- Ex: protective outer layer of skin
155
What are microtubules? What is their function?
- Tiny, hollow tubules that are the thickest of the cell fibers
- Made of protein subunits arranged in a spiral fashion
- Move things around the cell
156
What is the role of the centrosome?
- An area of the cytoplasm near the nucleus that coordinates the building and breaking of microtubules in the cell
- Plays an important role during cell division
157
What pulls the chromosomes apart during mitosis?
Microtubules
158
What kind of extensions does the cytoskeleton form?
Projections that extend the plasma membrane outward to form tiny, fingerlike processes
159
What structure forms the microvilli cell extension?
Microfilaments
160
What structure forms the cilia and flagella cell extension?
Microtubules
161
What is a downside to a microtubule?
- They're used to link cells together
| - Permits infection spread (motile organisms are able to travel from cell to cell)
162
Where is microvilli found? What is their function?
- Found in epithelial cells that line the intestines and other areas where absorption is important
- Increase surface area
163
What is the structure of cilia and flagella?
- Cell processes that have cylinders made of microtubules at the core
- Cilia are shorter and more numerous than flagella
164
Where is flagella found in humans?
ONLY in human sperm cells
165
How are cells held together? (2)
- Fibrous nets that surrounds groups of cells (e.g. muscle cells)
- Direct connections
166
What are the three types of direct cell connections?
1. Gap junctions
2. Tight junctions
3. Anchoring junctions
167
What are desmosomes?
- Physical link
- Links skin cells
- Anchored internally by intermediate filaments of the cytoskeleton
168
Differentiate spot and belt desmosomes.
- Spot: connecting adjacent membranes; spot welds at various points
- Belt: encircle the entire cell like a collar
169
______ junctions are communication bridges.
Gap
170
What are the two effects of gap junctions?
1. Form gaps that join the cytoplasm of two cells
| 2. Fuse two plasma membranes into a single structures
171
How do gap junctions work?
Membrane channels of adjacent plasma membranes adhere to each other
172
What kind of junction does the heart use? Why?
- Gap junction
- A single nerve impulse can travel to and stimulate the heart to contract all at once
- Allows for complete contraction and filling/emptying of the heart
- Areas of low electrical resistance
173
Individual cardiac muscle cells are joined by __________.
intercalated discs
174
What are the two types of connections within intercalated discs?
- Desmosomes
| - Gap junctions
175
Do the atria and ventricles form separate functional syncytium?
- Yes
- Allows for coordinated contraction and complete emptying
- So they contract at different times
176
What is the function of tight junctions? Give an example.
- Prevents movement of materials between cells
- Cells regulate what enters and leaves
- Ex: intestinal tract
177
What are anchoring junctions? Give an example.
- Cells attach to each-other, or the ECM
| - Ex: belt desmosome or spot desmosome
178
Why are tight junctions important in the intestine?
So that enzymes cannot reach underlying stroma layer
179
What type of cell is this: lots of lipid accumulation, lots of smooth ER. What type of system in the body?
- Hepatocytes (liver cells)
- Produces cholesterol (steroid hormones and bile)
- Accessory digestive organ
180
Name three types of lipids found in cell membranes.
- Phospholipids
- Sphingolipids
- Cholesterol
181
Which type of cell junction restricts movement of materials between cells?
Tight
182
Which type of cell junction allows direct movement of substances from the cytoplasm of one cell to the cytoplasm of an adjacent cell?
Gap
183
Which type of cell junction provides the strongest cell-cell junction?
Anchoring (Desmosome)
184
Which type of cell junction anchors actin fibers in the cell to the extracellular matrix?
Anchoring
185
List the five functional types of epithelia.
- Protective
- Secretory
- Transporting
- Cilitated
- Exchange
186
In a beaker with a semipermeable membrane, if the solution on the left is hypotonic compared with the solution on the right, which way will water move?
Right
187
What happens to a patient's red blood cells if the patient is given a hypertonic IV solution?
The cells will crenate, or shrink.
188
Which of the following must be equal inside the cell?
The number of positive and negative charges.
189
In the body, the majority of fluid is in which of the following fluid compartments?
A) Plasma
B) Intracellular
C) Interstitial
B) Intracellular
190
The cytoskeleton is NOT responsible for which of the following cellular movements?
A) transport of material into and within the cell
B) movement of DNA during cell division
C) diffusion of solutes
D) the sweeping strokes of ciliary action
C) Diffusion of solutes
191
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Cells that retain the ability to develop into specific cell types within a tissue are called __________.
A) stem cells
B) mitotic cells
C) totipotent cells
D) pluripotent cells
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A) Stem cells
192
Exocrine glands produce water secretions (ex: tears or sweat) called _________ secretions, or stickier solutions called _________ secretions.
serous, mucous
193
What three types of glands can be found within the skin? Name the secretion of each type.
- Sweat glands: sweat
- Apocrine glands: waxy or milky secretions
- Sebaceous glands: mixture of lipids
194
What forms the ECF?
- Interstital fluid
| - Plasma
195
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Unlike other intercellular junctions, ____________ only attach a cell to its neighbors at potential stress points.
A) tight junctions
B) adhering junctions
C) gap junctions
D) desmosomes
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D) desmosomes
196
What are the three basic components of connective tissue?
A) ground substance, cells, and basement membrane
B) cartilage, intercellular matrix, and serum
C) cells, protein fibers, and ground substance
D) collagen, elastin, and reticular fibers
C) cells, protein fibers, and ground substance
197
In apocrine glands, the secretory product is released
A) from a unicellular gland called a goblet cell
B) upon destruction of the entire gland cell
C) through exocytosis with no cellular damage
D) by pinching off the apical portion of the cytoplasm
D) by pinching off the apical portion of the cytoplasm
198
As long as ATP is available, the sodium/potassium pump of neurons will operate whether the neuron is resting, transmitting a nerve impulse, or returning to the resting state.
A) True
B) False
A) True
