Physiology Introduction Flashcards
1
Q
What is the study of all the physical and chemical processes that take place in organisms in order for them to perform all the functions and activities associated with living?
A
Physiology
2
Q
What can be studied at the molecular level all the way up to the level of entire organisms, and includes everything in between like cells, tissues, organs, and body systems?
A
Physiology
3
Q
What study involves studying how the different parts of the body work, separately and together, to allow an organism to function properly
A
Physiology
4
Q
The modern-day field of physiology has its roots in ancient cultures such as what countries?
A
India, Egypt, and Greece
5
Q
Who is the Ancient Greek philosopher that believed the body contained four important fluids called the “four humors”: phlegm, blood, yellow bile, and black bile.
A
Hippocrates
6
Q
The Ancient Greek philosopher Hippocrates believed that the body contained four important fluids called the?
A
four humors
7
Q
The Ancient Greek philosopher Hippocrates believed that the body contained four important fluids called the “four humors”: and those 4 are?
A
phlegm, blood, yellow bile, and black bile
8
Q
Who believed that if there was any disturbance in the amounts of these fluids in the body and their ratios to each other, a person would suffer from ill health
A
Hippocrates
9
Q
Hippocrates believed that if there was any disturbance in the amounts of these fluids(four humors) in the body and their ratios to each other, a person would suffer from?
A
ill health
10
Q
What fluid was thought to cause anger, irritability, and jealousy?
A
yellow bile
11
Q
What fluid was associated with being depressed, pessimistic, and withdrawn?
A
black bile
12
Q
too much yellow bile was thought to cause?
A
anger, irritability, and jealousy
13
Q
black bile was associated with being?
A
depressed, pessimistic, and withdrawn
14
Q
Four humors ideas were used in medicine from around?
A
420 B.C. all the way until the 1800s
15
Q
In what year, there was a paradigm shift when Matthias Schleiden and Theodor Schwann developed cell theory, which hypothesized that the body was made up of billions of individual cells?
A
1838
16
Q
Who are the developers of cell theory, which hypothesized that the body was made up of billions of individual cells?
A
Matthias Schleiden and Theodor Schwann
17
Q
In 1838, there was a paradigm shift when Matthias Schleiden and Theodor Schwann developed what theory? which hypothesized that the body was made up of billions of individual cells.
A
cell theory
18
Q
What theory was developed through the use of the compound microscope, a tool that became widespread in the 19th century and allowed for the advancement of many types of scientific knowledge
A
Cell theory
19
Q
Cell theory was developed through the use of what microscope? a tool that became widespread in the 19th century and allowed for the advancement of many types of scientific knowledge
A
compound microscope
20
Q
Cell theory was developed through the use of the compound microscope, a tool that became widespread in what century? and allowed for the advancement of many types of scientific knowledge
A
19th century
21
Q
The importance of physiology was reflected in? which began to be offered in the category of Physiology or Medicine in 1901
A
Nobel Prize
22
Q
The importance of physiology was reflected in Nobel Prize, which began to be offered in the category of Physiology or Medicine in what year?
A
1901
23
Q
The first Nobel Prize in Physiology or Medicine was awarded to? who performed pioneering research on treating diphtheria and tetanus
A
Emil von Behring
24
Q
The first Nobel Prize in Physiology or Medicine was awarded to Emil von Behring, who performed what research? on treating diphtheria and tetanus
A
pioneering research
25
The first Nobel Prize in Physiology or Medicine was awarded to Emil von Behring, who performed pioneering research on treating?
diphtheria and tetanus
26
Today, a main focus of physiology is on the ? at the cellular and molecular level, including diseases such as cardiovascular disease, diabetes, and cancers, along with immune responses
pathology and treatment of diseases
27
researchers study how cells carry out their processes and interact with each other. Two areas of interest include how molecules are transported across the cell membrane and how neurons transmit electrical impulses
Cell physiology
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looks at how physiology changes during embryonic development and also across the lifespan of an organism.
Developmental physiology
29
looks at how physiology has changed over many generations through evolution. It can incorporate behavior, sexual selection, and changes based on geographic range, among other factors.
Evolutionary physiology
30
this subfield emerged in the 1990s. It is the mathematical modeling of biological systems, and often focuses on components such as metabolism and cell-to-cell signaling. Researchers use computational models to better understand biological processes
Systems physiology (also known as systems biology)
31
the study of the processes that occur in the body during physical exercise. It also looks at the effects of exercise, some of which are long-term
Exercise physiology
32
are primarily composed of water, which in turn contains many substances.
body's fluids
33
group of substances includes electrolytes such as?
sodium, potassium, magnesium, phosphate, chloride, etc
34
group of substances includes metabolites such as?
oxygen, carbon dioxide, glucose, urea, etc
35
A third important group of substances is contained within our body's water, which includes? most of which are vital for our existence
proteins
36
Examples of proteins include?
coagulation factors, immunoglobulins, albumin, and various hormones
37
What % of the total body weight is comprised of water
60%
38
The body's fluid separates into 2 main compartments:
intracellular fluid volume (ICFV) and extracellular fluid volume
39
The two-thirds(66.6% of water in the body is within the what fluid?
Intracellular fluid space
40
The ECFV comprises 2 spaces:
The interstitial fluid volume (ISFV) and the plasma volume (PV)
41
One-third(33.3%) of the total body water is in the?
Extracellular fluid volume
42
What % of the extracellular fluid volume is present in the interstitial space
75%
43
Out of the extracellular fluid volume, 75% of the volume is present in the interstitial space, and what % of that water is in the plasma
25%
44
What consists of fluid between and around bodily tissue? Although technically a “virtual” space, this fluid bathes all the cells in the body and links between intracellular fluid and the intravascular compartment.
interstitial fluid
45
What is the only fluid compartment that exists
as a real fluid collection all in 1 space? It differs from the interstitial fluid by its higher protein content and its function in transportation. It is a component of blood and is said to be the “interstitial fluid of the blood” as it bathes the suspended red and white cells, which also reside in the blood.
Plasma
46
Several principles control the distribution of water between the various fluid compartments. To understand the different principles, it is essential to realize that ingestion and excretion of water and electrolytes are tightly regulated to maintain consistent?
total body water (TBW) and total body osmoparity(TBO)
47
Several factors mediate water redistribution between the 2 ECF compartments:
hydrostatic pressure, oncotic pressure, and the osmotic force of the fluid
48
What are typically barred from crossing the membrane but can occasionally cross via active transport or under specific conditions?
Ions
49
What can move freely across the membrane and is directed by the osmotic gradient between the 2 spaces?
Water
50
Changes in the ? result from alterations in the osmolarity of the ECF but do not respond to isosmotic changes in extracellular volume.
intracellular fluid volume
51
Any water flow in or out of the cell membrane has proportional changes in the?
ECFV
52
If a disturbance causes ECF osmolarity to increase, water flows out of the cell and into the extracellular space to balance the osmotic gradient; however, the total body osmolarity remains higher than what is typical, and the cell (shrink or swell)?
shrinks
53
If a disturbance were to cause a decrease in ECF osmolarity, then water would move from the ECF into the ICF to attain an osmolar equilibrium; however, the total body osmolarity would remain lower than normal, and the cell would (swell or shrink)?
swell
54
if this fluid entered the extracellular space, then there would be no net changes in the ICF, and the ECFV would increase.
isosmotic fluid
55
it is crucial to have a way to measure the volumes of the different compartments physically. The way to measure the different spaces is by using?
indicator-dilution method
56
What can be caused by a myriad of pathogens but is classically associated with isosmotic volume contraction. As the lost fluid isosmotic, there is no net effect on intracellular fluid; the only change is a decrease in ECF volume, with osmolarity remaining unchanged.
Diarrhea
57
In this condition, the body can either not produce ADH or the kidneys cannot respond to it, leading to a hyperosmotic volume contraction. In either case, there is a decrease in free water reabsorption from the distal tubules, leading to free water loss. In this scenario, the osmolarity of the ECF increases, leading to an inflow of water from the ICF to the ECF, leading to ICF volume constriction. However, this flow of water across the membrane into the ECF compartment is not enough to compensate for the loss of free water; thus, there is constriction of the EFV as well. Lastly, as water is lost from the ICF compartment, the osmolarity of the ICF increases. The same changes would be expected in severe burns and excessive sweating, where there is excessive loss of free water
Diabetes Insipidus
58
Conversely, excessive free water retention in ? results in the antithesis of what is seen in diabetes insipidus, leading to hypoosmotic volume expansion. In this condition, excess free water reabsorption in the distal tubule of the kidney leads to a decreased osmolarity of the ECF and an expansion of the ECFV. Due to the decrease in ECF osmolarity, water flows into the ICF compartment, expanding the ICFV and decreasing the osmolarity of the intracellular fluid.
SIADH
59
In this case, there is low aldosterone, primarily leading to decreased tubular sodium absorption and hypoosmotic volume contraction.In this case, sodium and water loss lead to decreased ECFV and decreased ECF osmolarity. Due to this decreased osmolarity, water shifts into the intracellular compartment, leading to ICFV expansion. Due to the decreased solute reabsorption, ICF osmolarity also decreases
Adrenal Insufficiency
60
Often found in kidney failure. BUN can increase. However, an isolated state of increased urea would not cause a shift in the volume of either compartment nor would it lead to a change in osmolarity. This is because these changes are only accompanied by the addition or subtraction of free water or an osmotically active particle, meaning a particle that cannot freely cross the cell membrane.As urea can freely cross the cell, it is considered non-osmotically active and, therefore, would not change osmolarity, thereby not leading to any shift of water balance.
Uremia
61
What is a fundamental concept in physiology that refers to the body's ability to maintain a stable internal environment despite external changes? It refers to a relatively stable set of conditions within an organism’s internal environment.
Homeostasis
62
Within the human body, maintaining a healthy environment for living cells requires maintaining appropriate conditions in the ?— including the interstitial fluid and blood plasma—for each living cell to be able to function properly.
extracellular fluids
63
There are three important conditions that must be met in order for the chemical reactions in the body to occur at the rates necessary for homeostasis:
- The first condition is that there must be a proper concentration of gases, nutrients, water, and salts
- The second important condition for homeostasis is an optimum temperature that is around 37°C
- The third and final condition is an optimum pressure
64
The first condition is that there must be a proper concentration of gases, nutrients, water, The gases involved are ?, which is necessary for the process of cellular respiration to produce energy for the body and salts.
oxygen
65
The first condition is that there must be a proper concentration of gases, nutrients, water, The gases involved are oxygen, which is necessary for the process of ? to produce energy for the body and salts.
cellular respiration
66
What is a waste product of cellular respiration but also must be present in certain amounts for other processes to occur efficiently?
Carbon dioxide
67
What provide reactants, enzymes, cofactors, and energy for chemical reactions?
Nutrients
68
What determine the fluid balance, electrolyte balance, and the pH of the body?
water and salts
69
The second important condition for homeostasis is an optimum temperature that is around?
37°C
70
The rates of chemical reactions are temperature dependent, typically occurring slower at what temperature?
cooler temperatures
71
The rates of chemical reactions are temperature dependent, typically occurring faster at what temperature?
warmer temperatures.
72
the shapes of ? are temperature dependent—if they overheat, they may denature and be rendered non-functional
proteins
73
The concentrations of various substances in the body and the rates at which these substances move through the body are both dependent on?
blood pressure
74
What is influenced by the volume of blood in the cardiovascular system, the diameter of the blood vessels and the strength of cardiac muscle contraction?
Blood pressure
75
What is maintained within the internal environment of the body?
Homeostasis
76
What is composed of cells surrounded by extracellular material, which is mostly fluid.
human body
77
What are responsible for controlling bodily activities and also controlling the composition of the environment around them?
Cells
78
What is defined as the fluid inside the body but outside of cells?
Internal environment
79
The fluid inside the cells in the body is the intracellular fluid, also called?
cytoplasm
80
What fluid is found in blood (i.e. plasma), in tissues (i.e. interstitial fluid), in the lymphatic system (i.e., lymph), in joints (i.e., synovial fluid), in the eyes (i.e., aqueous and vitreous humors), and in the central nervous system (i.e., cerebrospinal fluid)?
Extracellular fluid
81
The three main fluid types within the extracellular compartment are:
plasma, interstitial fluid and lymph
82
What is the liquid portion of blood and functions to move red and white blood cells, platelets, nutrient molecules, gases, electrolytes, and wastes throughout the circulatory system?
Plasma
83
Materials are exchanged at ? where the blood vessel walls are thin enough to allow materials to move between the blood and the tissues.
capillary beds
84
The fluid that surrounds living cells within tissues is called ?, which has a unique composition relative to both intracellular fluid and blood plasma.
interstitial fluid
85
must be returned to the circulatory system in order to maintain appropriate pressure within the cardiovascular system and for waste removal from cells.
Interstitial fluid
86
However, the interstitial fluid is under lower pressure than the plasma in the capillaries, and so only what percentage of the interstitial fluid is returned directly back to the circulatory system at the capillaries?
85%
87
The remaining 15% of interstitial fluid is returned indirectly through the vessels of another system called?
lymphatic system
88
The fluid in the vessels of lymphatic system , now called ?, is derived from tissue fluid(interstitial fluid)but is different from it in composition. It is collected into larger lymphatic vessels that eventually drain into veins close to the heart.
lymph
89
A constant internal environment is impossible to maintain
Stressors
90
What is continually subjected to disturbances that, unless counteracted, would quickly cause a new set of conditions in the body that could result in illness or death?
internal environment
91
What is any stimulus that causes an imbalance in the
internal environment. It may be factors external to the
body or from within the body itself.
stressor
92
What is the physiological value around which the normal range fluctuates?
set point
93
What is the restricted set of values that is optimally healthy and stable?
normal range
94
What is a mechanism that reverses a deviation from the set point. Therefore, this mechanism maintains body parameters within their normal range. The maintenance of homeostasis by this mechanism occurs throughout the body at all times, and an understanding of this mechanism is thus fundamental to an understanding of human physiology.
Negative feedback
95
What detects when the stressor/stimulus produces a deviation in a physiological value away from the set point?
sensor, also referred to a receptor
96
What is the component in a feedback system that compares the value to the normal rang?
control center
97
A sensor, also referred to a receptor, detects when the stressor/stimulus produces a deviation in a physiological value away from the set point. This change in value is reported to the?
control center
98
If the value deviates too much from the set point, then the control center activates an?
effector
99
What is the component in a feedback system that produces a response, which in the case of a negative feedback loop, causes a return of the physiological value to its normal range?
effector
100
In a negative feedback loop, a ? Is a deviation from a set point—is resisted through a physiological process that returns the body to the set point.
stimulus
101
in the control of blood glucose, what cells in the pancreas detect excess glucose (stimulus) in the bloodstream?
endocrine cells (receptors)
102
in the control of blood glucose, specific endocrine cells (receptors) in the pancreas detect excess glucose (stimulus) in the bloodstream. What cells respond to the increased level of blood glucose?
pancreatic beta cells (control center)
103
in the control of blood glucose, specific endocrine cells (receptors) in the pancreas detect excess glucose (stimulus) in the bloodstream. These pancreatic beta cells (control center) respond to the increased level of blood glucose by releasing what hormone ? into the bloodstream
insulin
104
in the control of blood glucose, specific endocrine cells (receptors) in the pancreas detect excess glucose (stimulus) in the bloodstream. These pancreatic beta cells (control center) respond to the increased level of blood glucose by releasing the hormone insulin into the bloodstream. The insulin signals ? to take up the excess glucose (response), removing it from the bloodstream.
skeletal muscle fibers, fat cells (adipocytes), and liver cells (effectors)
105
The brain’s temperature regulation center is called?
hypothalamus
106
When the brain’s temperature regulation center in the hypothalamus receives data from the sensors indicating that the body’s temperature exceeds its normal range, it stimulates a cluster of brain cells referred to as the?
thermoregulatory center
107
What vessels in the skin begin to dilate, allowing more blood from the body core to flow to the surface of the skin and allowing heat to radiate into the external environment.
Blood vessels
108
As blood flow to the skin increases, what glands are activated to increase their output?
sweat glands
109
The depth of respiration increases, and a person may breathe through an open mouth instead of through the nasal passageways. This further increases heat loss from the?
lungs
110
In contrast, activation of the thermoregulatory center by exposure to cold reduces blood flow to the skin, and blood returning from the limbs is diverted into a network of?
deep veins
111
If heat loss is severe, what triggers an increase in random signals to skeletal muscles, causing them to contract and producing the shivering response. The muscle contractions involved in shivering release heat while using ATP.
hypothalamus
112
The brain triggers the thyroid gland in the endocrine system to release the ?, which increases metabolic activity and heat production in cells throughout the body.
thyroid hormone
113
The hypothalamus also signals the adrenal glands to release ?, a hormone that causes the breakdown of glycogen into glucose, which can be used as an energy source. The breakdown of glycogen into glucose also results in increased metabolism and heat production
epinephrine (adrenaline)
114
What intensifies a change in the body’s physiological condition rather than reversing it. Its loops employ the same five basic components as negative feedback loops, with the difference being that a deviation from the normal range results in more change, and the system moves farther away from the set point
Positive feedback
115
What part of the contains stretch-sensitive nerve cells that monitor the degree of stretching uterus?
cervix
116
stretch-sensitive nerve cells send messages to the brain, which in turn causes the pituitary gland at the base of the brain (the control center) to release a hormone into the bloodstream called?
oxytocin
117
What hormone causes stronger contractions of involuntary smooth muscles in the uterus (the effectors), pushing the baby farther down the birth canal?
Oxytocin
118
What involves intricate mechanisms that work together to regulate various physiological parameters?
Homeostasis
119
What are central to homeostasis. They involve a series of events that act to counteract any changes in a regulated parameter. When a variable deviates from its set point, the body initiates responses that bring it back to the desired range.
Negative feedback loops
120
What play essential roles in maintaining homeostasis. They detect changes in the internal environment, integrate information, and initiate appropriate responses to restore equilibrium.
Control system
121
What monitors and responds to changes in the internal environment through sensory receptors. It transmits signals to various target organs to initiate appropriate physiological responses.
nervous system
122
What releases hormones into the bloodstream, which act as chemical messengers to regulate bodily functions. Hormones play a vital role in maintaining homeostasis by influencing target cells and organs.
endocrine system
123
What system in kidneys help regulate the body's fluid balance, electrolyte concentrations, and acid-base balance. They filter blood, reabsorb essential substances, and excrete waste products to maintain internal equilibrium.
Renal System
124
What maintains body temperature within a narrow range. It involves the integration of signals from thermoreceptors, activation of cooling or heating mechanisms, and coordination of responses to ensure optimal temperature control.
thermoregulatory system
125
Homeostasis ensures optimal conditions for cellular function, including the maintenance of appropriate pH levels, nutrient availability, and waste removal.
Cellular Function
126
Homeostasis allows different organ systems to work together harmoniously. It ensures that all systems, such as the cardiovascular, respiratory, and digestive systems, function in sync to support overall bodily functions
Organ System Coordination
127
Homeostasis enables the body to adapt to changes in the external environment, such as temperature fluctuations or changes in nutrient availability. It helps maintain stability and ensures appropriate responses to external stimuli.
Adaptation to Environmental Changes
128
Imbalances in homeostasis can lead to various health conditions. Understanding the physiology of homeostasis is crucial in identifying disruptions and developing interventions to restore equilibrium.
Health and Disease
129
- 1. These cells are the simplest cells without a nucleus and cell organelles.
- 2. These cells are the smallest cells (1-10 μm).
- 3. Unicellular and earliest to evolve (~4 billion years ago), still available.
- 4. The cell wall is rigid.
- 5. These cells reproduce asexually.
- 6. They include bacteria and archaea.
- 7. Some species are highly evolved pathogens e.g., Borrelia burgdorferi.
Prokaryotic cells
130
- 1. These cells are sophisticated cells with a well defined nucleus and cell organelles.
- 2. The cells are comparatively larger in size (10-100 μm).
- 3. Unicellular to multicellular in nature and evolved ~1 billion years ago.
- 4. The cell membrane is semipermeable and flexible.
- 5. These cells reproduce both asexually and sexually.
- 6. Include the animals, plants and fungi.
- 7. Size ranges from tiny yeasts to giant sequoias, dinosaurs, etc.
Eukaryotic Cells
131
Thin layer of protein and fat that surrounds the cell is called the ? It is semipermeable, allowing some substances to pass into the cell and blocking others.
cell membrane
132
Jelly-like material present outside the nucleus in which the cell organelles are located. It is the site of protein synthesis and many metabolic events. This material contains many enzymes for general metabolism. It contains fibre of the cytoskeletal system, which organizes cytoplasmic structure.
Cytoplasm
133
Spherical to rod-shaped organelles with a double membrane. It is known as the power house of the cell as it generates ATP (adenosine triphosphate), the energy currency of the cell.
Mitochondria
134
The inner membrane of mitochondria is in-folded many times, forming a series of projections called?
cristae
135
Small organelles composed of RNA-rich cytoplasmic granules that are sites of protein synthesis. Its size is measured in Svedberg (S) units; derived from sedimentation in ultracentrifuge (used before electron microscopes were available).
Ribosome
136
It is a spherical body containing many organelles, including the nucleolus. It controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes). It is surrounded by the nuclear
membrane. It is the locus of DNA/RNA synthesis and protein assembly. It contains chromatin i.e., DNA-protein complexes.
Nucleus
137
What can condense into chromosomes during cell division?
Chromatin
138
What is a double layered structure surrounding the nucleus containing many nuclear pores?
nuclear membrane
139
What is present within the nucleus. Some cells have more than one of this. It is the assembly plant for ribosomes
nucleolus
140
A small body located near the nucleus, also called the ‘microtubule organizing centre’. It has a dense center and radiating tubules. This is where microtubules are made.
centrosomes
141
What is the dense centre of the centrosome?
centriole
142
A vast system of interconnected, membranous, in-folded and convoluted sacks that are located in the cell’s cytoplasm. It is covered with ribosomes that give it a rough appearance. It transports materials through the cell
Rough endoplasmic reticulum (rough ER)
143
Rough endoplasmic reticulum (rough ER) synthesizes proteins in sacks called ? for export or movement to different cell organelles like the Golgi body, or inserted into the cell membrane but not to cytoplasm.
cisternae
144
A vast system of interconnected, membranous, in-folded and convoluted tubes that are located in the cell’s cytoplasm. It transports materials through the cell. It contains enzymes which produces and digests lipids (fats) and membrane proteins; it buds off from rough ER, moving the newly-made proteins and lipids to the Golgi body, lysosomes and membranes. It detoxifies drugs and poisons (in liver)
Smooth endoplasmic reticulum (smooth ER)
145
The space within the ER is called the?
ER lumen
146
A flattened, layered, sac-like organelle that looks like a stack of pancakes. It is located near the nucleus. It produces the membranes that surround the lysosomes. The Golgi body packages proteins and carbohydrates into membrane-bound vesicles for export from the cell. Functions as intracellular ‘post office’ for sorting new proteins made on rER.
Golgi body (Golgi apparatus or Golgi complex)
147
These are round organelles surrounded by a membrane where the digestion of cell nutrients takes place due to presence of the digestive enzymes. They contain —40 hydrolytic enzymes such as lipases, proteases, nucleases, etc. which break down organic polymers of all types. Lysosomes continuously break down old proteins, foreign materials, and many wastes. They also bring about phagocytosis, a process in which foreign materials are brought into the cell and ‘chewed up’.
Lysosomes
148
Sometimes lysosomes open up in cell itself causing death of the cell termed as ?, hence are called suicide bags of the cell.
apoptosis
149
Fluid-filled, membrane-surrounded cavities inside a cell. This fills with food being digested and waste material that is on its way out of the cell.
vacuole
150
These are single membrane oval or spherical cellular organelles. They contain catalase enzyme. They are involved in the oxidation of long chain fatty acids and synthesis of plasmalogens and glycolipids.
Peroxisomes (micro bodies)
151
152
It provides internal fibrous structure to cells because cell is not ‘just a bag in a bubble’, it contains lots of internal fibres or internal ‘skeleton’. It is not rigid like bone, instead it is capable of being assembled, allows cell movement, cell division, internal motion of the organelles and is broken down in minutes.
Cytoskeletal system
153
The cytoskeletal system is composed of?
microtubules and microfilament
154
What have the largest diameter among the fibres found in the cytoplasm of all eukaryotes. It involves many structures: Cilia, flagella, spindle fibres that polymerize from centrioles during mitosis/meiosis.
microtubules
155
microtubules are made of the protein called?
tubulin
156
They are organelles of locomotion. Both of them contain 9 double rings of microtubules, 2 central microtubules, two motor proteins, i.e., motor protein 1-dynein and motor protein 2-kinesin, which allow motion along microtubules
Cilia and flagella
157
Another kind of fiber found in cytoplasm of most eukaryotes. Involved in muscle contraction, cell support, pinching off of daughter cells after mitosis.
Microfilaments (actin)
158
Animal cells do not have cell walls, but have? a meshwork of macromolecules outside plasma membrane. It consists mainly of glycoproteins (proteins with oligosaccharide chains), especially collagen.
Extracellular matrix (ECM)
159
Specialized ‘belts’ that bind two cells tightly to each other, prevent fluid from leaking into intracellular space.
Tight junctions
160
Intercellular ‘rivets’ that create tight bonds between cells, but allow fluids to pass through intracellular spaces.
Desmosomes
161
Formed by two connecting protein rings embedded in cell membrane of adjacent cells. Allows passage of water, small solutes, but not proteins, nucleic acids.
Gap junctions
