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