bio final exam
____ speeds up the conduction of action potentials
Myelin
composed of one or two modified amino acids
Amino acid-derived hormones
The human thermostat, located in the hypothalamus of the brain, is set at ____
97-99ºF
is provided by B cells and the antibodies that they secrete into the blood that attack pathogens outside the body's cells
Humoral immunity
- prevent most pathogens from entering the body - Includes skin and cilia, and secretions such as tears, saliva, and mucus
Nonspecific external barriers
the ideal defenses are barriers that prevent invaders from entering the body in the first place
Nonspecific external barriers
Vertebrate animals have three major lines of defense against disease. what are they?
Nonspecific external barriers Nonspecific internal defenses Specific internal defenses
Receptors for hormones are found in two general locations on target cells:
On the plasma membrane Inside the cell, within the cytoplasm or the nucleus
controls involuntary movement
autonomic nervous system
- An iodine-deficient diet can reduce the production of thyroxine and trigger a feedback that attempts to restore normal hormone levels by increasing the number of thyroxine-producing cells - The thyroid gland becomes enlarged, forming a condition called ____
goiter
plays an important role in the formation of long-term memory and is thus required for learning
hippocampus
The adaptive immune system simultaneously launches two types of attack against microbial invaders:
humoral immunity cell mediated immunity
The _______ is a part of the brain that contains clusters of specialized nerve cells called neurosecretory cells that synthesize peptide hormones
hypothalamus
causes tissues to become warm, red, swollen, and painful
inflammatory response
Steroid hormones usually bind to receptors ___ target cells
inside
The voltage inside the cell is always ____ and ranges from about _____
negative -40 to -90 millivolts (mV)
often called nerve cells, which receive, process, and transmit information
neurons
The nervous system has two principal cell types:
neurons glia
Most synaptic terminals contain ____ that are released from one cell and bind receptors on another cell
neurotransmitters
The _____ combat invading microbes
nonspecific internal defenses
bind to receptors for natural endorphins and produce a feeling of euphoria
opiates like heroin or morphine
Humoral immunity fights pathogens that are _____ of cells because antibodies are large proteins that cannot enter cells.
outside
When microbes cause disease, they are called
pathogens
appear to influence transitions between sleep and wakefulness
pons
Sex hormone levels increase during ____, which is the phase of life in which reproductive systems become mature and functional
puberty
Approximately ____ of U.S. citizens will eventually contract some form of cancer
40%
B cells and cytotoxic T cells are ineffective without assistance from helper ____
T cells
A typical synapse consists of:
- The synaptic terminal, found at the end of an axon of one cell - A dendrite of another cell - A small gap separating the two cells
A nervous system must be able to perform four operations:
1 Determine the type of stimulus 2 Determine and signal the intensity of a stimulus 3 Integrate information from many sources 4 Initiate and direct appropriate responses
It takes _____ to mount a strong immune response after the first exposure to an invading microbe
1 or 2 weeks
Antibodies combat microbes in 3 ways:
1. Bind to a pathogen and render it harmless by a process called neutralization - An example of neutralization is an antibody covering the active site of a toxic enzyme in snake venom 2. Coat the surface of pathogens and make it easier for phagocytic cells to destroy them - Macrophages recognize the antibody stems sticking out into the blood, then engulf the antibody-coated pathogens 3. Antibodies can interact with complement proteins that are always present in the blood - Some of the complement proteins punch holes in the plasma membranes of the microbe, killing it - Other complement proteins promote phagocytosis of the invaders
Four of these regulate hormone production in other endocrine glands:
1. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) 2. Thyroid-stimulating hormone (TSH) 3. Adrenocorticotropic hormone (ACTH)
All adaptive immune responses include the same three steps:
1. Lymphocytes recognize an invading microbe and distinguish the invader from self 2. They launch an attack 3. They retain a memory of the invader that allows them to ward off future infections by the same type of microbe
- Immune deficiency diseases occur when the body cannot mount an effective immune response - _______, where a viral infection destroys a formerly functional immune system by destroying helper T cells.
Acquired immune deficiency syndrome (AIDS)
causes the release of the hormone cortisol from the adrenal cortex
Adrenocorticotropic hormone (ACTH)
Antibiotics slow down microbial reproduction - _____ are chemicals that help to combat infection by slowing down the multiplication of bacteria, fungi, or protists Antibiotics are not effective against viruses
Antibiotics
- Each B cell has its own unique antibodies on its surface - when an infection occurs, the antibodies found on only a few B cells can bind to antigens on the invader - ____-antibody binding causes these B cells, but no others, to divide rapidly
Antigen humoral immunity
The key cellular players in the adaptive immune response are _____, which arise from stem cells in the bone marrow
B cells and T cells
_____ will kill more than 500,000 people in the United States this year
Cancer
are required to fight viruses once they have entered body cells
Cell-mediated immune reactions
is produced by a type of T cell called the cytotoxic T cell that attacks infected body cells, killing both the cell and any pathogens inside it
Cell-mediated immunity
Typical neurons have four distinct parts that carry out these four functions:
Dendrites A cell body An axon Synaptic terminals
Methods of communication between cells fall into four broad categories:
Direct Synaptic Paracrine Endocrine
_______ hormones, on the other hand, are released into the bloodstream, move throughout the body in a few seconds, and trigger responses that may last from a few seconds to a lifetime
Endocrine
- ___ can act as an endocrine organ - In 1995, Jeffrey Friedman at Rockefeller University discovered the peptide hormone leptin, which is released by fat cells - Mice genetically engineered to lack the gene for leptin became obese, and leptin injections caused them to lose weight - Leptin "tells" the body how much fat it has stored and therefore how much to eat - This molecule is currently being studied as a possible weight-loss supplement (Pennington)
Fat
____ combats large-scale infections
Fever
stimulate the production of sperm and testosterone in males and the production of eggs, estrogen, and progesterone in females
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
acts on nearly all the body's cells by increasing protein synthesis, promoting the use of fats for energy, and regulating carbohydrate metabolism - too little growth hormone results in dwarfism, and too much results in gigantism
Growth hormone
- ____ relaxes the smooth muscle surrounding arterioles, increasing blood flow and causing capillary walls to become leaky - Extra blood flowing through leaky capillaries drives fluid from the blood and into the wounded area, causing redness, warmth, and swelling
Histamine
This defense mechanism has several functions:
It attracts phagocytes to infected or injured tissue It promotes blood clotting It initiates protective behavior by causing pain
Three important types of phagocytes are:
Macrophages Neutrophils Dendritic cells
_____ cells play a role in both the innate and adaptive immune responses
Macrophages and dendritic
include bacteria, protists, and fungi; and viruses,
Microbes
- If the external barriers are breached, a variety of nonspecific internal defenses swing into action - include: White blood cells, which engulf foreign particles or destroy infected cells Chemicals released by damaged cells and proteins released by white blood cells that trigger inflammation and fever - These operate regardless of the nature of the invader, neutralizing the threat
Nonspecific internal defenses
_____ causes contractions of uterine muscles during childbirth and triggers "milk letdown" in nursing mothers by causing muscle tissue within the mammary glands of breasts to contract in response to stimulation by the suckling infant
Oxytocin
prepares the reproductive tract to receive and nourish the fertilized egg
Progesterone
in conjunction with other hormones, stimulates the development of milk-producing mammary glands in the breasts during pregnancy
Prolactin
The remaining hormones of the pituitary do not act on other endocrine glands
Prolactin Growth hormone
_______ are modified fatty acid hormones that contribute to inflammation and pain sensations Drugs such as aspirin, acetaminaphen, and ibuprofen provide relief from these symptoms by blocking the enzymes that synthesize prostaglandins
Prostaglandins
- The final line of defense is the adaptive immune response, in which immune cells selectively destroy specific invading microbes and toxins and then remember the invader - This allows for a rapid response to the invader if it reappears in the future
Specific internal defenses
- ______ communication is used in the nervous system - Electrical signals within individual nerve cells send information to the farthest reaches of the body in a fraction of a second - At a synapse, a nerve cell communicates with a target cell by releasing chemicals, called neurotransmitters, across a tiny space between the nerve cell and its target
Synaptic
in males, promotes sperm production and stimulates the development of male secondary sexual characteristics, including body and facial hair, broad shoulders, and muscle growth
Testosterone
consists of the medulla, pons, and cerebellum
The hindbrain
The major endocrine glands and organs are:
The hypothalamus-pituitary complex The thyroid gland The pancreas The sex organs The adrenal glands
what consists of the endocrine hormones and the glands that produce them
The mammalian endocrine system
The first line of defense consists of two surfaces with direct exposure to the environment
The skin The mucous membranes of the digestive, respiratory, and urogenital tracts
stimulates the thyroid gland to release its hormones
Thyroid-stimulating hormone (TSH)
_____, or thyroid hormone, is an iodine-containing amino acid derivative that stimulates glucose breakdown and elevates the metabolic rate of many body cells
Thyroxine
destroy invading cells or the body's own cells if they've been infected by viruses
White blood cells, called leukocytes or phagocytes,
When the first 2 levels of defense are breached, the body mounts a highly specific and coordinated _____ directed against a particular organism to destroy it, and provide future protection against that microbe but no others
adaptive immune response
consists of three major components: immune cells, tissues and organs, and secreted proteins
adaptive immune system
The _____ are located at the top of each kidney and secrete hormones that regulate metabolism and responses to stress
adrenal glands
- Slows reaction time and slurs speech by blocking receptors for glutamate. - Provides a pleasant "buzz" by blocking dopamine reuptake. - Blocks pain by releasing endorphins. - Increases feelings of happiness by modifying an increasing our serotonin receptors.
alcohol
massive dopamine release
amphetamines
clusters of neurons produce sensations of pleasure, fear, or sexual arousal when stimulated
amygdala
The cerebrum contains 2 key areas of the brain
amygdala hippocampus
proteins, produced by B cells and their offspring
antibody
Lymphocytes generate two types of proteins that recognize, bind, and help to destroy specific antigens:
antibody t cell receptor
These large, complex molecules are called _____, because they are "antibody generating" molecules that can provoke an immune response, including the production of antibodies
antigens
In a typical neuron, a long, thin strand called an ____ extends outward from the cell body and conducts signals from the cell body to synaptic terminals at the axon's end
axon
Electrical signals travel down the dendrites and enter the neuron's _____, which processes the information it receives
cell body
The nervous system of all mammals, including humans, can be divided into two parts:
central nervous system peripheral nervous system
consisting of the brain and spinal cord
central nervous system (CNS),
crucial for maintaining coordination of the body. Involved in motor learning (practicing a repeated task)
cerebellum
Both heavy and light chains consist of a ______, which is similar in all antibodies of the same type, and a ______ that differs among individual antibodies
constant region, variable region
Cell-mediated immunity, produced by ______, is the body's primary defense against cells that are cancerous or that have been infected by viruses
cytotoxic T cells
The outer surface of the skin consists of dry, ______ filled with tough proteins that do not allow the microbes to obtain the water and nutrients they need to survive
dead cells
branched tendrils protruding from the cell body that perform the "receive information" function
dendrites
Lack of insulin production or the failure of target cells to respond to insulin results in ____
diabetes mellitus
- In _____ communication, tissues such as heart muscle have gap junctions that directly link the insides of adjacent cells, allowing ions and electrical signals to flow between them - this type of communication is very fast, but also has a very short range
direct
The midbrain also contains neurons that produce the transmitter _____
dopamine
Affect the nervous system more than they affect any other body system.
drug and alcohol
- The adrenal glands produce two hormones in response to stress or exercise: ____ - These hormones prepare the body for emergency action by increasing the heart and respiratory rates, increasing blood pressure, causing blood glucose levels to rise, and directing blood flow away from the skin, digestive tract and toward the brain and muscles - "White as a ghost"
epinephrine and norepinephrine
from the ovaries of females stimulates breast development and the maturation of the female reproductive system, including egg production
estrogen
The ovaries secrete two types of steroid hormones: ____
estrogen and progesterone
produced when microbes cause a major infection in the body, which both slows down microbial reproduction and enhances the body's own fighting abilities
fever
includes the thalamus, hypothalamus, and cerebrum. This is also the location of the limbic system that is evolved in emotion, pleasure, and reward.
forbrain
assist neuronal function
glia
direct the activities of the autonomic nervous system, and maintains homeostasis by influencing body temperature, food intake, water balance, heart rate, blood pressure, the menstrual cycle, and circadian rhythms.
hypothalamus
recruits leukocytes to the site of a wound and seals off the injured area, isolating the infected tissue from the rest of the body
inflammatory response
Microbes that penetrate the skin or mucous membranes encounter an array of internal defenses, collectively called _____
innate immunity
The endocrine portion of the pancreas consists of clusters of islet cells that produce one of two peptide hormones: ____
insulin and glucagon
what control glucose levels in the blood
insulin and glucagon
Fever also stimulates virus-infected cells to produce a protein called ____, which makes surrounding, non-infected cells more resistant to infection.
interferon
Sweat and sebaceous glands secrete natural antibiotics, such as _____, that inhibit the growth of many bacteria and fungi
lactic acid
Lymph is extracellular fluid that flows through the _____, which contain masses of macrophages and specialized white blood cells called lymphocytes
lymph nodes
The inflammatory response begins when damaged cells release chemicals that cause certain cells in the connective tissue, called _____, to release _____
mast cells histamine
controls several automatic functions, such as breathing, heart rate, blood pressure, and swallowing
medulla
Some of the daughter cells of the original B cells, cytotoxic T cells, and helper T cells that responded to the original infection differentiate into ______ cells and memory______ that survive for many years
memory B T cells
which do not release antibodies but play an important role in future immunity to the invader that stimulated their production
memory b cells
Humoral immunity (continued) - The daughter cells differentiate into two cell types:
memory b cells plasma cells
contributes to movement, arousal, and emotion
midbrain
Antimicrobial secretions, mucus, and ciliary action defend the ____
mucous membranes against microbes
In addition to variable thickness, neurons can increase the rate of action potential conduction by covering portions of the axon with a fatty insulation called _____
myelin
In _____ communication, cells release chemicals to other cells in the immediate vicinity They influence only a small group of cells, but do so quickly because the distances are very short
paracrine
chains of amino acids
peptide hormone
There are three classes of vertebrate endocrine hormones:
peptide hormones amino acid derived hormones steroid hormones
consisting of neurons that lie outside the CNS and the axons that connect these neurons with the CNS
peripheral nervous system (PNS),
Elevated body temperature increases _____ and slows ____
phagocytic activity bacterial reproduction
- Hormones are also produced by the pineal gland, thymus, kidneys, heart, digestive tract, and fat cells - The ___ is located between the two hemispheres of the brain and produces the hormone ____ - This hormone is secreted in a daily rhythm, which in mammals is regulated by light entering the eyes - Melatonin is thought to regulate our sleep cycles
pineal gland melatonin
which become enlarged and produce a huge quantity of specific antibodies that are released into the bloodstream
plasma cells
Antibodies may function as ______, binding to specific antigens and eliciting a response to them, or as ______, helping them destroy cells or molecules that bear the antigen
receptors effectors
- Neurosecretory cells of the hypothalamus produce at least seven hormones that regulate the release of hormones from the anterior pituitary - These hypothalamic hormones are called _______
releasing hormones or inhibiting hormones.
An un-stimulated, inactive neuron maintains a constant electrical voltage difference, or potential, across its plasma membrane
resting potential
- These hormones cannot diffuse through the phospholipid bilayer of the plasma membrane and must bind to receptors on the surface of the target cell's plasma membrane - Hormone-receptor binding activates an enzyme that synthesizes a molecule, called a _____, inside the cell - An example is ______, which regulates many cellular activities
second messenger (cyclic AMP)
controls voluntary movement
somatic nervous system
The peripheral nervous system consists of two parts:
somatic nervous system autonomic nervous system
The _____, found in the abdomen, filters blood, exposing it to white blood cells that destroy foreign particles and aged red blood cells
spleen
synthesized from cholesterol
steroid hormones
Dendrites respond to _____
stimuli such as pressure, odor, light, body temperature, blood pH, or the position of a joint
Peptide and amino acid hormones usually bind to receptors on the ____ of target cells
surfaces
- T-cell receptors are found only on the ______ - They have highly specific binding sites for antigens, but unlike antibodies, T-cell receptors are never released into the bloodstream, and they do not directly contribute to the destruction of invading microbes or toxic molecules
surfaces of T cells
The site where a neuron communicates with another cell
synapse
proteins, produced by T cells
t cell receptor
Besides producing sperm or eggs, the _____ in males and _____ in females are also important endocrine organs
testes ovaries
The testes secrete several steroid hormones, the most important being ____
testosterone
a complex relay station that also helps filter sensory information
thalamus
If the membrane potential becomes less negative, it reaches a level called _____ and triggers an action potential
threshold
The _____ is a gland located beneath the breastbone, slightly above the heart, and is essential for development of some immune cells
thymus
Lying in front of the neck, just below the larynx, is the ____, which produces two hormones: thyroxine and calcitonin
thyroid gland
The best solution would be to develop a ____
vaccine against HIV
Innate immune responses fall into three categories:
white blood cells inflammatory response fever