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Biol 112 > Chapter 32 > Flashcards

Chapter 32 Flashcards

1
Q

Homeostasis

A

A condition in which the internal environment of the body remains relatively constant despite changes in the external environment.

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2
Q

Why is homeostasis so important?

A

Failure to maintain homeostasis results in imbalances, later causing sickness, disease, and death.

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3
Q

Lowest heart rate occurs at what time of the day?

A

Around 3am because we are asleep, so we have slower heartbeat.

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4
Q

Morning hypertension occurs around what time?

A

Around 7am because of the rapid rise in blood pressure.

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5
Q

What time of the day is the highest risk of cardiac arrest?

A

Around 10am because of dehydration and the constriction of blood vessels.

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6
Q

What time of the day does a person have the fastest reaction time?

A

Around 3pm.

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7
Q

What time of the day does a person have the greatest muscle strength?

A

Around 7pm.

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8
Q

What time of the day does the secretion of melatonin begin?

A

Around 9pm. Pineal melatonin secretion occurs during the nighttime. Melatonin secretion involves the regulation of the human circadian core body temperature.

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9
Q

Levels of biological organization:

A

Cell- Tissue- Organ- Organ System- Organism

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10
Q

What function does the cell membrane perform to maintain homeostasis?

A

Cell membranes help organisms maintain homeostasis by transporting or moving material in and out of the cell.

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11
Q

What methods of transport are responsible for exchange across the cell membrane?

A

Passive, active, and bulk transports

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12
Q

How does the size of a cell effect exchanges made by the cell to it’s environment?

A

The size of a cell directly affects how it exchanges with its environment. Exchange is effective over very short distances. A large cell is limited by the distance materials must travel from the center of the cell to its surface, which ultimately causes the cell to not satisfy metabolic demands.

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13
Q

How does exchange work in single cell organisms?

A

Exchange occurs by simple diffusion. Exchange is simple because the organism is small in size and has direct contact with external environment (lives in water).

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14
Q

How does exchange work in multicellular organisms?

A

Exchange occurs by simple diffusion. Each cell has its own plasma membrane, so each layer of cells is in direct contact with the external environment.

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15
Q

How does exchange work in complex multicellular organisms?

A

Cells are embedded inside the organism and therefore isolated from direct contact with the external environment. Exchange surfaces include digestive, respiratory, and circulatory systems, meaning large organisms need more specialized transport systems or diffusion would be too slow.

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16
Q

How can cells with no direct contact with the external environment make exchanges?

A

Those needs are met by the internal environment, namely the extracellular fluid which allows for the movement of material into and out of the cells.

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17
Q

Passive Transport

A

Does not use the cell’s energy in brining materials in and out of the cell.

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18
Q

Active Transport

A

Does use the cell’s energy in bringing materials in and out of the cell.

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19
Q

Bulk Transport

A

Involves the cell making membrane bound vesicles to bring materials in and out the cell.

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20
Q

What two components make up the extracellular fluid?

A

Plasma and interstitial fluid.

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21
Q

Plasma

A

Fluid portion of blood.

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22
Q

Interstitial fluid

A

Fluid that surrounds the cells, sometimes referred to as tissue fluid.

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23
Q

What is the role of extracellular fluid?

A

Connects all cells to the external environment so no matter where a cell is located it can make the exchanges essential to life.

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24
Q

What level of biological organization enables the exchanges between the internal and external environments?

A

Organ systems

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25
What is the primary function of the cell membrane?
It allows certain materials to enter and exit the cell.
26
Interstitial fluid and plasma are both considered _______ fluid and make up the ________ of the body.
intracellular; internal environment
27
Interstitial fluid is...
the route for the exchange of materials between blood and body cells.
28
Cell is...
the smallest unit of life
29
Tissue is...
an organized group of cells, working together as a functional unit
30
What are the 4 types of tissues?
Epithelial, connective, muscle, nervous
31
Where is epithelial tissue located?
Cover the surface of the body and lines the cavities within the body.
32
What are the two surfaces of connective tissue?
Apical surface is the free side that faces away from other tissues. Basolateral surface is the secured side which is tightly bound to neighboring cells.
33
Epithelial tissues are classified according to...
Shape (squamous, cubodial, columnar) and Layers (simple or stratified)
34
Function of connective tissue is...
mainly binds and supports other tissues
35
Loose connective tissue:
binds epithelial cells to underlying tissues and holds organs in place
36
Dense connective tissue:
has more collagen fibers. Includes tendon (attaches muscle to bone) and ligament (attaches bone to bone).
37
Blood:
is composed of blood cells and cell fragments in the blood plasma. (classified as a tissue, does not connect but transports)
38
Cartilage:
is a strong and flexible support material
39
Adipose tissue:
stores fat for insulation and fuel
40
Hyaline cartilage:
flexible and resilient and not easily compressed, within joints and nose
41
Elastic cartilage:
is flexible and bendable yet rigid, ear and larynx
42
Fibrocartilage:
is sturdy, tough and inflexible, knee
43
What is the function of muscle tissue?
It is responsible for all types of body movement.
44
What do muscles consist of?
They consist of filaments of the proteins actin and myosin, which enable muscles to contract.
45
What are the three types of muscle tissue?
Skeletal, Cardiac, and Smooth
46
Smooth Muscle
- No striations, spindle shaped cells - Single nucleus in each cell - Found in the walls of blood vessels and visceral organs - Involuntary contractions
47
Skeletal Muscle
- Striated appearance - Cells are multinucleated - Attached to bone by tendons - Voluntary contractions
48
Cardiac Muscle
- Striated and branched appearance - Single nucleus - Contain gap junctions - Involuntary contractions
49
What is the function of Nervous Tissue?
Sense stimuli and transmit information. It coordinates, regulates, and integrates many body functions.
50
What does nervous tissue consist of?
Neurons and glial cells
51
Neuron function
transmit nerve impulses
52
Glial cells function
support cells and supply nutrients
53
The four principal types of tissues are:
Epithelial, connective, muscle, nervous
54
How does size relate to the speed of diffusion?
Diffusion will be the most rapid when the size of the cell is the smallest/thinnest
55
Blood is classified aa a(n) ______ tissue.
Connective
56
Nerve cells are essential to an animal because they directly provide...
communication between cells
57
What is the function of organ systems?
Work together to maintain homeostasis.
58
Communication usually occurs via the control and coordination of which two systems?
Endocrine system and Nervous system
59
Endocrine system
- Does not have ducts to carry away their secretions | - Hormones pass directly into bloodstream for distribution around the body
60
Exocrine system
- Does consist of ducts to carry away their secretions out of the body
61
Coordination and Control of the Endocrine system
Endocrine cells transmit chemical signals called hormones. These hormones travel through the body via blood.
62
How does the function of hormones work?
Hormones can reach all parts of the body but only cells with a matching receptor will respond.
63
Coordination and Control of the Nervous system
Nervous system transmits signals between specific locations via nerve impulses which travel along neurons
64
Partners in Homeostasis: Endocrine system
- Hormones - Slow acting, long lasting - Adapted for growth and development, reproduction, digestion
65
Partners in Homeostasis: Nervous system
- Nerve impulses - Fast acting, short lived - Adapted for fast movement and behavior
66
Control system function
Regulate large external fluctuations in external environment into small fluctuations in the internal environment
67
What is the primary mechanism of homeostasis?
Negative feedback
68
Negative feedback
- produces a response that restores the normal balance | - reverses the direction of change
69
Positive feedback
- amplify a change - rare in biological systems - does not usually contribute to homeostasis in animals
70
What are the three functional components to homeostatic regulation?
Sensor, integrating center, and effector
71
Sensor
- membrane protein | - detects a stimulus or a changing condition outside and within the body
72
Integrating Center
- control center - compares condition to a set point - if conditions are too far from the set point, biochemical reactions are initiated to change condition back to set point
73
Effector
- cell or organ | - responds to the command and produces a response to either oppose or enhance the stimulus
74
In a negative feedback mechanism, the response of the effector...
Reverses the activity of the original stimulus
75
Why is thermoregulation important?
Thermoregulation helps animals maintain their internal temperature within a set of range that is optimal for survival of body cells.
76
Thermoregulation in humans
- core body temperature is maintained
77
How does the human body measure temperature?
Hypothalamus. The hypothalamus contains a group of nerve cells that function as a thermostat.
78
Where does the hypothalamus receive signals from that detects temperature?
- Peripheral thermo-receptors in the skin | - Central thermoreceptors in the hypothalamus and CNS
79
What happens if your body detects the body as too warm?
Vessels dilate (vasodilation) in the skin and sweating begins
80
What happens if your body detects the body as too cold?
Vessels constrict (vasoconstriction) and shivering begins
81
Endothermic animals
- body chemistry regulates our temperature and keeps it constant - uses metabolism to generate heat and regulate their body temperature - can generate heat and have mechanisms for cooling Examples: mammals and birds
82
Ectothermic animals
- gain their heat from their environment, not from metabolism - adjust their temperature by behavioral means like basking in the sun and seeking shade Examples: invertebrates, fish, amphibians, reptiles
83
Disadvantages of being an Endotherm
- energetically expensive | - need more food than ectotherms
84
The homeostatic thermostat which facilitates the process of thermoregulation is present in the...
hypothalamus
85
If body temperature decreases, what wouldn't occur?
sweating
86
An ectotherm is:
An animal whose body temperature changes depending on the temperature of the environment
87
An endotherm is:
An animal who can maintain a stable body temperature internally
88
Which of the following is NOT an example of a homeostatic mechanism?
Using blankets to cover up when the body feels cold
89
Thermoregulation depends on what?
An animal's ability to exchange heat with its environment.
90
What are the five methods of thermoregulation?
(1) Insulation, (2) circulatory adaptations, (3) cooling by evaporative heat loss, (4) behavioral responses, (5) adjusting metabolic heat production
91
Insulation
- reduces heat flow between animal and its environment | Sources: hair, feathers, layers of fat formed by adipose tissue
92
Circulatory Adaptations
- change in vessel diameter | - countercurrent heat exchange
93
Countercurrent heat exchange
Warmer arterial blood flowing from the body's core transfer heat to cooler venous blood returning from the extremities
94
Cooling by Evaporative Heat Loss
- sweat production increases when the body begins to overheat - sweat absorbs heat when it evaporates
95
Behavioral Responses
- Change of location (sun or shade) - Change of position (movement to increase metabolic rate) - Huddling to conserve heat
96
Adjusting Metabolic Heat Production
- shivering (increased contraction of muscles) - hormones (cause mitochondria to produce heat instead of ATP) - Brown fat (turn food into body heat) * Only human newborns and hibernating mammals have high levels of brown fat
97
How do animals energy budget?
They reduce their basal metabolic rate (BMR) which helps save energy.
98
What does energy budgeting produce?
Produces a state of dormancy called Torpor.
99
Torpor can be:
Daily (bats at night, hummingbirds at night) and Long-Term (hibernation and estivation)
100
Function of the Immune System
protects the body by fighting infection and cancer
101
Lymphatic Organs
Primary Lymphatic Organs: red bone marrow, thymus | Secondary Lymphatic Organs: lymph nodes, spleen, tonsils
102
Primary Lymphatic Organ: Red Bone Marrow
- site of blood cell production | - B cells are produces and mature here
103
Primary Lymphatic Organ: Thymus
- Bilobed; in the thoracic cavity superior to the heart - Shrinks as we age - Functions: produces thymosin (induces the maturation of T cells) and T cells mature and reside here
104
Secondary Lymphatic Organ: Spleen
- filters blood - upper left region of the abdominal cavity - connective tissue divides it into white pulp and red pulp
105
Macrophages
- located in red pulp | - removes pathogens, debris, and worn out red blood cells from the blood
106
Lymph nodes
- found along the lymphatic vessels - filter lymph - filled with macrophages that engulf pathogens and debris - house lymphocytes, which fight infections and cancer cells
107
Cytokines
produced by macrophages, B lymphocytes, T lymphocytes and mast cells
108
Antigens
proteins that are foreign to the organism
109
Antibodies
proteins produced by your body that bind to specific antigens
110
Natural killer cells
- kills virus infected and cancerous cells | - kills cells that lack surface proteins
111
T cells
- regulate immune responses; produce cytotoxic T cells and helper T cells - T cells are unable to recognize an antigen without antigen-presenting cells, such as a macrophage
112
When does the activation of a T-cell occur?
When its T-cell receptor (TCR) can combine with an antigen presented by a macrophage.
113
How do Cytotoxic T cells kill infected cells?
1. Cytotoxic t cells bind to virus infected cell 2. Perforin is released and punches holes in the plasma membrane, forming a pore 3. Granzymes are delivered into the pore 4. Apoptosis occurs in the virus infected cell
114
What is the function of Helper T cells?
secrete cytokines that enhance the response of all types of immune cells
115
Passive Immunity
- Antibodies pass from mother to fetus via placenta or to infant via the mother's milk - Preformed antibodies in immune serum are introduced by injection
116
Active Immunity
- Antigens enter the body naturally; body induces antibodies and specialized lymphocytes - Antigens are introduced in vaccines; body produces antibodies and specialized lymphocytes
117
Tissue Rejection
- Rejection of transplanted tissue results because the recipient's immune system recognizes that the transplanted tissue is not "self" - Cytotoxic T cells attack the transplanted tissue
118
Acquired Immune Deficiency
results from infection with the human immunodeficiency virus (HIV)
119
Autoimmune Disease
- Cytotoxic T cells attack the body's own cells as if they were foreign
120
Rheumatoid Arthritis
- Inflammation in skeletal joints | - T-cells deteriorate the joints
121
Multiple Sclerosis (MS)
- T cells attack the myelin sheath covering nerve fibers | - Causes central nervous system dysfunction, double vision, and muscular weakness

Biol 112 (2 decks)

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