Biology Systems Flashcards
1
Q
Classification of Organisms
A
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (dear king philip cried out for good soup)
2
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Domains
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Bacteria, Archaea, and Eukarya
3
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Kingdoms of Eukarya Domain
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Protista, Fungi, Plantae, and Animalia
4
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Class and phylum of mammals
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Class- mammalia; phylum- chordata
5
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Species
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loosely limited to all organisms that can reproduce to create fertile offspring
6
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Causes for differentspecies being unable to mate
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geographic isolation, temporal isolation (mating in different seasons), genetic incompatibility
7
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Genotype
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describes the chromosomes of an organism
8
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Phenotype
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describes the products of the genes that can be observed
9
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Allele
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copy of a gene
10
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Polymorphism
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a gene that has multiple alleles corresponding to distinct forms of a phenotype whose existence in a population makes evolution possible
11
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Gene pool
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the total of all alleles in a population
12
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Evolution
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the change in a population’s gene pool
13
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Speciation
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the formation of a new species which is when members from a single species have evolved into different groups that can no longer produce fertile offspring
14
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Mechanisms that contribute to speciation
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inbreeding, bottleneck situation, specialization, and adaptation
15
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Inbreeding
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the mating of relatives which increases the number of homozygous individuals in a population without changing the allele frequency
16
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Outbreeding
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mating of nonrelatives which maintains genetic flow between populations and so would not be expected to contribute to speciation
17
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Bottleneck
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sharp reduction in the population size where the allelic frequencies of the survivors are not representative of the original population
18
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Specialization
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the process by which the members of a species tailor their behaviors to exploit their environment; when distinct groups within a population specialize such that they differ substantially ie. in habits or locations, speciation may result
19
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Adaptation
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genetic or behavioral changes that are advantageous in a given environment
20
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Assumptions of Hardy-Weingberg Equilibrum
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- mutational equilibrium 2. large population 3. random mating 4. immigration or emigration must not change the gene pool 5. no natural selection
21
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Measurement of evolutionary time
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by comparing the genomes of species that share a common ancestor can be used to determine how long ago they diverged due the gradual changes in the genome
22
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Genetic drift
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changes in the gene pool in a small population owing to the chance of disappearance of alleles for individuals who fail to reproduce or die
23
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Sexual selection
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selection of certain phenotypes for mating
24
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Fitness concept
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the fittest organism is the one that can best survive to reproduce offspring who will in turn reproduce offspring and son generation after generation
25
Measure of gene fitness
increase in percent representation in the gene pool of the next generation
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Natural selection
genes that are advantageous in a given environment are preferentially passed down from generation to generation
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Differential reproduction
those organisms best adapted to an environment will be most likely to survive to reproductive age and have their own offspring
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Viruses
tiny infectious agents from 1 to 100s of genes in the form of DNA or RNA (not both) that have the ability to transfer genetic material and are comparable in size to large proteins
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Capsid
protein coat of a virus
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Viral particle/virion
a mature virus outside the host cell
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Structure of a virus
capsid (containing nucleic acid), lipid-rich protein envelope (for some viruses), and tail, base plate, and tail fibers for most bacteriophages
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Host cell
the cell that is being infected by a virus
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Receptor that virus binds to
usually a specific glycoprotein on the host cell membrane
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Bacteriophage
a virus that infects bacteria which typically injects nucleic acids into the host cell through its tail after viral enzymes have digested a hole in the cell wall
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Bacteriophage Injection Mechanism
Landing, Attachment, Tail contraction and penetration, injection
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Eukaryotic Virus Infection Mechanism
being engulfed by an endoctytotic process
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Lytic infection
the virus comandeers the cell's synthetic machinery to translate its RNA into proteins which self-assemble to form a new virus; the cell may fill with new viruses until it lyses
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Latent period
the period from infection to lysis
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Virulent virus
a virus following a lytic cycle and which is capable of causing disease
40
Lysogenic infection
the viral DNA is incorporated into the host genome where the host cell replicates its DNA in addition to the viral DNA; may show no symptoms of infection
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Temperate virus
a virus in the lysogenic cycle
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Provirus (or prophage in bacteria)
when the viral DNA remains incorporated in the host DNA (dormant/latent)
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Activation of dormant virus
potentially when the host cell is under stress in which the virus then takes on a lytic phenotype
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Synthetic machinery
parts of cell used to produce protein
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Viral envelope
formed as viruses undergo exoctyosis from the cell and to a certain extent protects the virus from detection by the immune system
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Enveloped virus
protects virus from detection by the host cell's immune system and allows it to bind to a new host cell and start the process all over again
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Nonenveloped virus
typically lyse a cell and cause cell death on their release
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Viral RNA
may have plus-strand RNA which only requires translation to produce proteins or it may have a minus-strand RNA which involves transcription/replication of RNA and then translation of that RNA to produce protein
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Retrovirus
able to transcribe their RNA into double stranded DNA
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Reverse transcriptase
enzyme that transcribes RNA into DNA
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HIV
human immunodeficiency virus is a retrovirus that attacks cells involved in the immune response
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Subviral particles
infectious agents related to viruses which include viroids and prions
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Viroids
small rings of naked RNA without capsids which only infect plants
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Prions
naked proteins which cause infections in animals and are capable of reproducing themselves without DNA or RNA
55
Prokaryotes
do not have membrane bound organelles including a nucleus and are split into two domains: bacteria and archae
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Archae
prokaryote with similarities to both bacteria and eukaryotes which are typically found in extreme environments such as salty lakes and boiling hot springs
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Shapes of Bacteria
cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped)
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Symbiotic
mutually beneficial relationship ie. bacteria in the intestinal tract of humans
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Parasitic
the relationship is beneficial to one organism but hurts the other
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Anaerobic
not dependent on oxygen for growth and survival
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Aerobic
requires oxygen for growth and survival
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Protoplast
the bacterial plasma membrane along with everything it contains
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Bacterial envelope
surrounds the protoplast
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Cell wall
component of the bacterial envelope adjacent to the plasma membrane
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Peptidoglycan
makes up the cell wall of bacteria and consist of a series of disaccharide polymer chains with amino acids and these chains are crosslinked by an interbridge of more amino acids
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Gram positive bacteria
the cell wall is located just outside the cell membrane and have a thick peptidoglycan cell wall; stain purple
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Gram negative bacteria
contain a thin peptidoglycan cell wall which is located in between two plasma membranes, the outer membrane possesses lipopolysaccharides which protrude outward and form a protectibe barrier from antibodies and antibiotics; stain pink
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Flagella
long, hollow, rigid, helical structures that rotate counterclockwise to propel the bacterium in a single direction
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Flagellin
globular protein which flagella are made from in bacteria
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Flagellar propulsion
allows bacteria to move toward favorable products such as food sources
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Chemotaxis
the directed movement of a motile cell or organism toward substances that will promote its survival and growth
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Binary fission
a type of asexual reproduction (by bacteria) which results in 2 genetically identical daughter cells
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Genetic recombination
examples are sexual reproduction, conjugation, transformation, and transduction
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Origin of replication
point where DNA replication begins
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Growth of bacterial population
exponential growth, meaning that each bacteria produces 2 offspring and so on
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Conjugation
the transfer of a plasmid from one bacterium to another
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Plasmid
small circles of extragenomic DNA which are not essential to the survival of bacteria that carry them
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Extragenomic DNA
DNA that exist and replicate independently from the chromosome
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Episome
a plasmid that can integrate into the chromosome
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F plasmid
the fertility factor or F factor because it codes for the sex pilus (a conjugative plasmid)
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R plasmid
donates resistance to certain antibiotics (also a conjugative plasmid)
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Transformation
the process by which bacteria incorporate DNA from the external environment into their genomes
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Transduction
the transfer of genetic material by a virus when a bacteriophage mistakenly encapsulates a DNA fragment of the host cell and injects this bacteria DNA into another cell
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Vector
a virus that mediates transduction
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Transposons
provides a way for nucleotides to move from one position to another along the genome
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Transposase
the enzyme that catalyzes the transposon's removal from and incorporation into the chromosome
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sex pilus
a hollow protein tube that connects two bacteria to allow the passage of the plasmid from one to the other (conjugation)
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Photosynthetic autotroph
organisms that obtain energy from sunlight
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Nucleus
contains all of the DNA in a eukaryotic cell, other than a small amount in the mitochondria
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Nuclear envelope
double phospholipid bilayer wrapped around the nucleus
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Nuclear pores
large holes in the nuclear envelope in which RNA can exit but DNA cannot
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Nucleolus
an area within the nucleus where rRNA is transcribed and the subunits of the ribosomes are assembled
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Endoplasmic Reticulum
organelle that is a thick maze of membranous walls in the eukaryotic cell separating the cytosol from the ER lumen; proteins that will ultimately be exported from the cell or sequestered in a vesicle are translated on the ER
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Cisternal space
ER lumen
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rough ER
ER near the nucleus which has many ribosomes attached to its cytosolic side, giving it a granular appearance; synthesizes all proteins that do not belong in the cytosol; proteins synthesized in rough ER are pushed into ER lumen and sent to Golgi; also synthesizes peptide hormones
96
Golgi apparatus
a series of flattenened, membrane bound sacs whose major functions are packaging and secreting proteins within vesicles to be expelled from the cell, to mature into lysosomes, or transported within the cell ; may alter proteins by glycosylation or by removing amino acids;
97
Lysosomes
type of vesicle that contain hydrolytic enzymes particularly acid hydrolase that digest substances taken in the cell by endocytosis; come from Golgi apparatus
98
Apoptosis
programmed cell death where lysosomes are seen in high concentration as they rupture their contents to kill the cell
99
Smooth ER
plays a role in lipid metabolism and storage, as well as detoxification
100
Adipocytes
cells containing predominantly fat droplets which contribute to energy storage and body temperature regulation
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Peroxisome
vesicles in the cytosol that are involved in both lipid and protein storage and are involved in the production and breakdown of hydrogen peroxide
102
Hydrogen peroxide
a byproduct that has potential to harm the cell, broken down by peroxisomes
103
Mitochondria
site of ATP production
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Endosymbiotic theory
mitochondria may have evolved from a symbiotic relationship between ancient prokaryotes and eukaryotes and contain ciruclar DNA that replicates independently from nuclear DNA and contain no histones or nucleosomes; have their own ribosomes
105
Inner mitochondrial membrane
invaginates to form cristae and holds the electron transport chain of aerobic respiration
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Intermembrane space
space between inner and outermembrane of mitochondria
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Cytoskeleton
network of filaments that contributes to a cell's structure and motility; consists of microtubules, microfilaments, and intermediate filaments
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Microtubules
provide a platform for transport within cells and also support the shape of the cell; made up of globular protein tubulin
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Microtubule organizing center (MTOC)
- end of microtubule attaches to MTOC and the the microtubule grows away from MTOC at is + end
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Centrosome
major MTOC in animal cells, composed of a pair of centrioles
111
Centrioles
function in the production of flagella and cilia but are not necessary for microtubule production
112
cilia
specialized structure made from microtubules (along with flagella); they function to move fluid, causing the cell itself or nearby substances to move
113
9+2 arrangement
9 pairs of microtubules that forma circle around 2 lone microtubules where each outer pair is connected to its neighbot by dyneinthat are the major portion of each flagellum and cilium
114
Dynein
protein that connects each outer pair of microtubule to its neighbor in the 9+2 arrangment causing microtubule pairs to slide along their neighbors creating a whip action in cilia that causes fluid to move laterally or wiggle action in flagella which causes fluid to move directly away from the cell
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Microfilaments (actin filaments)
interact with myosin to cause muscle contraction and are responsible for cleavage during cytokinesis
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Intermediate filaments
maintain the cell's shape and primarily serve to impart structural rigidity to the cell
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Eukarytoic flagella vs prokaryotic flagella
eukaryotic: 9+2 arrangement, whip-like action; prokaryotic: thin strand of flagellin, rotate
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Micelle
when placed in aqueous solution, amphipathic molecules spontaneously aggregate, turning their polar ends toward the solution and their nonpolar ends toward each other resulting in a spherical structural
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Integral or intrinsic protein
amphipathic proteins that can cross the membrane from inside of the cell to the outside
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Peripheral or extrinsic protein
located on the surfaces of the membrane and are generally hydrophilic; generally ionically bonded to integral proteins or the polar group of a lipid
121
Fluid mosaic model
the fluid part refers to the phospholipids and proteins which can slide past each other since the forces holding the entire membrane together are intermolecular; the mosaic part refers to the asymmetrical layout of a membrane's lipids and proteins
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Functions of membrane proteins
transporter, receptor, attachment, identifier, adhesion, and enzyme
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Brownian motion
the random movement of molecules moving rapidly and in all directions and leads to the tendency of solutions to mix completely with each other over time
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Chemical concentration gradient
series of vectors pointing in the direction of lower concentration
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Electrical gradient
pointing in the direction that a positively charged particle will tend to move
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Semipermeable
membrane slows the diffusion of X but does not stop it
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Factors that determine permeability of compound
size and polarity
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Leakage channels
most of the diffusion of polar or charged molecules across a membrane take place through incidental holes created by the irregular shapes of integral proteins
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Passive diffusion
when molecules move across a membrane through random motion such as through a leak channel
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Membrane channels/carrier proteins
facilitate the diffusion of specific molecules or ions across the membrane
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Facilitated diffusion
use of carrier or membrane channels for passive diffusion; contributes to the selective permeability of the membrane by selecting between molecules of similar size and charge
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Active transport
requires expenditure of energy
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Secondary active transport
powered indirectly by ATP to create an electrochemical gradient which is then used to acquire or expel a molecule down its concentration gradient ie. sodium potassium pump
134
Isotonic
aqueous solution of their cytosol contains approximately the same concentration of particles as the aqueous solution surrounding them
135
Hypertonic cells
cells that are more concentrated than their environment
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Hypotonic cells
cells that are less concentrated than their environment
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Osmotic pressure
minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane
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Colligative property
a property that is based on the number of particles present rather than the type of particle
139
Endocytosis
how cells acquire substances from the extracellular environment
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Phagocytosis
the cell membrane protudes outward to envelop and engulf particulate matter; triggered by the binidng of particulate matter to protein receptors on phagocytic cell; performed by particular cells
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Phagosome
the membrane bound bond of a particulate mater that is engulfed by phagocytosis
142
Pinocytosis
extracellular fluid is engulfed by small invaginations of the cell membrane and is typically performed by most cells and random, non-selective
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Receptor-mediated endocytosis
specific uptake of macromolecules such as hormones and nutrients; in this process the ligand binds to a receptor protein on the cell membrane and is then moved to a clathrin-coated pit which then invaginates to form a coated vesicle
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Exocytosis
reverse of endocytosis; provides a way for substances to leave the cell
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Interphase
G1, S, and G2
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G1 stage
cell has just divided and begins to grow in size, producing new organelles and proteins; RNA and protein synthesis are highly active
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G0 stage
a non-growing state distinct from interphase; responsible for variations in the length of cell cycle between different types of cells
148
S stage
the cell devotes most of its energy to DNA replication; organelles and proteins are produced more slowly
149
M stage
mitosis or meiosis which is defined by the division of the nucleus
150
G2 stage
the cell prepares to divide; organelles continue to duplicate, RNA and proteins are actively produced
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Cancer
unchecked cell growth
152
Mutations that cause cancer
tumor repressor: the deactivation of a checkpoint protein; oncogene: the activation of a gene that causes the proliferation of the cell
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Tissue
group of similar cells that work together
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Fibroblasts
secrete fibrous proteins such as elastin and collagen which form a molecular network that holds tissue cells in place (the extracellular matrix)
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Basal lamina
a thin sheet of matrix material that separates epithelial cells from support tissue; also found around nerves, and muscle and fat cells; usually acts as a sieve-like barrier, selectively allowing the passage of some molecules but not others
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Epithelial cells
separate the outside environment from the inside of the body
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Support tissue
composed of the cells adjacent to epithelial cells on the inside of the body
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Types of intercellular junctions
tight, desmosomes, and gap
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Tight junctions
form a watertight seal from cell to cell that can block water, ions, and other molecules from moving around and past these cells; often found in epithelial tissue of bladder, intestines, and kidneys
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Apical surface
the part of a cell facing the lumen of a cavity
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Basolateral surface
the part of a cell opposite of the lumen of a cavity
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Desmosomes
join 2 cells at a single point; attach directly to the cytoskeleton of each cell, and are found in tissue that typically experience a lot of stress ie. skin or intestinal epithelium; strongest type of junction
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Gap junctions
small tunnels that connect cells, facilitating the movement of small molecules and ions between the cells; found in cardiac muscle to propagate action potential from cell to cell, and in some kinds of smooth muscle allowing fibers to contract as a unit
164
Intracellular second messenger
activates or deactivates enzymes and/or ion channels and often creates a cascade of chemical reactions that amplifies the effect of the hormone
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Epithelial tissue
separates free body surfaces from their surrounidngs; includes endothelium which lines vessels of the body such as the heart
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Connective tissue
characterized by an extensive matrix such as blood, lymph, bone cartilage, and connective tissue proper
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Positive sense virus
contain coding RNA that can be immediately transcribed by the host ribosomes and thus do not require RNA-dependent RNA polymerase (RdRP)
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Negative sense virus
contain the complement of the coding strand; since human cells do not normally make RNA from other RNA, there is no way for these viruses to begin replication without RdRP
169
Speed of communication of nervous system
specific and fleeting; somatic more so than autonomic
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Nervous system
includes the brain, spinal cord, nerves, neural support cells and sense organs such as the eye and the ear
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Neuron
the smallest functional unit of the nervous system; a highly specialized cell capable of transmitting a signal from one cell to another through a combination of electrical and chemical processes
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Dendrites
stubby structures that receive a signal to be transmitted
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Structure of neuron
dendrites, cell body, and axon
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Summation
provides a way for the nervous system to screen for the most important stimuli
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Spatial summation
occurs when multiple dendrites receive signals at the same time
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Temporal summation
adds up the effects of signals that are received by a single dendrite in quick succession
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Frequency of firing
codes the intensity of a stimulus of sensory neurons
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Axon hillock
the site of connection between the cell body and the axon
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Axon
carries action potentials to a synapse; having a single axon minimizes error and maximizes efficiency since multiple synapses would provide opportunities for information to be transferred incorrectly and would also slow down the signal
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Receptors
bind substances (ligands) such as neurotransmitters and respond by triggering responses within the cell
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Ion channels
open to allow ions to travel from one side of the membrane to the other, facilitating the transmission of signals; vary in how quickly they open and close
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Concentration cell
differences in concentration initiate the movement of charge, creating a voltage
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Concentrations of Na and K across membrane
more Na outside the cell and more K inside the cell
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Resting potential
the electric potential or voltage across the neuronal membrane at rest; a stored potential that is used by the neurons to transmit a signal
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Sodium potassium pump
functions to maintain or reestablish the chemical gradient that is lost by diffusion; the pump moves ions against their concentration gradients using ATP; moves 3 Na+ out and 2 K+ in
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Resting potential of neuron
set up by the diffusion of K; K diffuses out of the cell, dragging along negatively charged proteins that get stuck along the inner side of the membrane; when the chemical gradient of K equilibriates, the inner side of the membrane is negatively charged compared to the outer side; resulting potential across the membrane is very close to equilibrium potential of K
187
Action potential
mechanism by which a signal travels down the length of a neuron and ultimately is transferred to the next cell; generated by a change in voltage across the neuronal membrane
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Voltage gated Na channels
these proteins change configuration when the voltage across the membrane is disturbed allowing Na+ to flow through the membrane
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Depolarization
the process of the activation of multiple voltage gated Na channels causing more sodium channels to change configuration, allowing more sodium to flow into cell so that the cell becomes positive on the inside
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Voltage gated K Channels
less sensitive to voltage change than sodium channels, so they take longer to open
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Repolarization
the process of K+ flowing out of the cell, moving the potential back towards the negative equilibrium potential of K
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Hyperpolarization
the process when the potassium channels are so slow to close that the membrane potential becomes even more negative than the resting potential
193
Threshold stimulus
in order to create an action potential, the stimulus to the membrane must be greater than the threshold
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Excitatory
depolarizing effect
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Inhibitory
hyperpolarizing effect
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Accommodation
if the threshold is reached but it is reached very slowly so that an action potential may not occur
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Absolute refractory period
period in which no stimulus will create another action potential because the membrane potential is already more positive than the resting potential, so the driving force of the action potential is absent
198
Relative refractory period
the time during which only an abnormally large stimulus will create an action potential because the membrane is hyperpolarizing, requiring a greater threshold stimulus
199
Steps of action potential
1. membrane is at rest, voltage gated sodium and potassium channels are closed 2. voltage gated sodium channels open and the cell depolarizes 3. voltage gated potassium channels open as sodium channels begin to inactive 4. voltage gated sodium channels are inactivated, open potassium channels repolarize the membrane 5. voltage gated potassium channels close and the membrane equilibriates to its resting potential
200
Electrical synapse
composed of gap junctions between cells and are often used when coordinated action is required from a group of cells ie. cardiac muscle, visceral smooth muscle
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Chemical synapse
consists of a space between 2 neurons that is crossed by neurotransmitters; unidirectional
202
Motor end plate
the connection between a neuron and a muscle
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Neurotransmitters
chemicals that are often derived from amino acids which are released into the synapse by a presynaptic neuron and attach to receptors on the post-synaptic cell; required because the electrical signal of the action potential cannot be transferred across the synapse
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Fatigue (of presynaptic neuron)
when a presynaptic cell is fired too often and it is not able to replenish its supply of neurotransmiter vesicles so the impulse is not passed to the postsynaptic cell
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G protein second messenger system
a G protein is attached to the receptor protein along the inside of the postsynaptic membrane, when the membrane is stimulated by neurotransmitter, part of the G-protein called the alpha subunit breaks free and may activate separate specific ion channels, activate a second messenger, activate intracellular enzymes or activate gene transcription
206
Glial cells/neuroglia
support cells in nervous tissue; different types carry out immune functions, circulate cerebrospinal fluid, support ganglia, give physical support to neurons, help maintain the mineral and nutrient balance in the interstitial space, and create myelin
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Myelin
electrically insulating sheaths in the central nervous system that wrap many times around axons which acts as a insulator around the axon, increasing resistance to the passage of ions through the membrane
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Schwann cells
produce myelin in the peripheral nervous system which wrap their entire bodies around the axons
209
White matter
refers to areas of the nervous system that are composed of myelinated axons of neurons
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Grey matter
refers to bundles of the cell bodies of neurons
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Nodes of Ranvier
tiny gaps between the myelinated areas and are the only places along the myelinated axon where ions cross the neuron's membrane
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Saltatory conduction
the phenomenon when action potentials jump from one node of Ranvier to the next
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Sensory/afferent neurons
receive signals from a receptor cell that interacts with the environment and then transfers this signal to other neurons; located dorsally on the spinal cord
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Interneurons
transfer signals from neuron to neuron
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Motor/effector neurons
carry signals to a muscle or gland; located ventrally on the spinal cord
216
Effector
muscle or gland
217
Nerves
neuron processes (axons and dendrites) bundled together
218
Reflex
a quick response to a stimulus that occurs without direction from the CNS
219
Supraspinal circuits
circuits above the spinal cord
220
Central Nervous System
consists of the neurons and support tissue within the brain and spinal cord; a major function is to integrate nervous signals between sensory and motor neurons
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Peripheral Nervous System
handles the sensory and motor functions of the nervous system and is further divided into the somatic nervous system and autonomic nervous system
222
Somatic nervous system
contains sensory and motor functions and primarily functions to respond to the external environment
223
Autonomic nervous system
coordinates an involuntary response to environmental stimuli, altering processes within the body to produce the most adaptive physiological state and behavior; further divided into the sympathetic and parasympathetic nervous systems
224
Antagonistic control
when two systems have opposing influences on the same organs
225
Sympathetic nervous system
fight or flight; acts on the heart to increase heart rate and stroke volume and around organs of the digestive and excretory systems in order to divert more blood flow to skeletal muscles; increased blood glucose and basal metabolism signals originate in the spinal cord; short preganglionic neurons, long postganglionic neurons; however does not innervate skeletal muscle
226
Parasymapthetic nervous system
rest and digest; slows the heart rate and increases digestive and excretory activity; signals originate in both the brain and spinal cord; long preganglionic neurons, short postganglionic neurons
227
Nucleus
a group of cell bodies located in the CNS
228
Ganglion
a group of cell bodies located outside the CNS
229
Acetylcholine
the neurotransmitter used by all preganglionic neurons in the ANS (and somatic) and by postganglionic neurons in the parasympathetic branch
230
Epinephrine or norepinephrine
the neurotransmitter used by postganglionic cells of the sympathetic nervous system
231
Cholinergic receptor
receptor for acetylcholine
232
Adrenergic
receptor for epinephrine and norepinephrine
233
Brainstem
controls the basic involuntary functions necessary for survival; includes the medulla, pons, and midbrain
234
Medulla
plays an important role in the regulation of cardiovascular and respiratory systems and monitor levels of CO2 in the bloodstream and triggers changes in the respiration rate accordingly
235
Pons
coordinates communication between the motor cortex and the cerebellum, facilitating the transfer of motor commands
236
Cerebellum
heavily involved in the coordination and planning of movement
237
Diencephalon
thalamus and hypothalamus collectively
238
Thalamus
control center; processes almost all sensory information before it reaches higher cortical centers as well as receiving motor commands from these cortical areas on their way to the spinal cord
239
Hypothalamus
regulates many of the body's basic physiological needs by maintaining homeostasis in multiple systems such as temperature and water balance
240
Cerebrum/cerebral cortex
the most recently evolved portion of the brain and is the location of many higher-level functions of the nervous system such as consciousness, memory, cognition, planning, and emotion
241
Frontal lobe
the location of higher-level (executive) function such as planning and impulse inhibition; includes motor cortex
242
Motor cortex
creates a map of the parts of the body such that specific sets of neurons control certain body parts
243
Parietal lobe
contains the somatosensory cortex
244
Somatosensory cortex
maps the body's sensation of touch
245
Somatosensory system
involves the detection of physical stimuli such as touch, temperature, and pain
246
Occipital lobe
the site where visual information is processed
247
Temporal lobe
primarily concerned with auditory and olfactory information
248
Limbic system
primarily concerned with memory and emotion
249
Lateralization of cortical functions
take place primarily in one hemisphere or the other; production/comprehension of language: left hemisphere; positive emotion: left; negative emotion: right
250
Methods of studying the brain
lesion studies, imaging, and recording of electrical activity
251
Sensory receptors
detect internal and external stimuli
252
Mechanoreceptors
respond to the physical stimuli of touch and pressure change
253
Thermoreceptors
respond to temperature change
254
Nociceptors
respond to pain
255
Electromagnetic receptors
respond to light
256
Chemoreceptors
respond to taste, smell, and blood chemistry; important for maintenance of homeostasis throughout the body
257
Photoreceptors
type of electromagnetic receptor; detect the physical stimulus of photons that enter the eye; do not generate action potentials but instead the relative level of light affects the rate of neurotransmitter release by the photoreceptors into the synapses that they share with sensory neurons
258
Sensory adaptation
a stimulus that occurs repeatedly at the same intensity level evokes fewer and fewer action potentials in the sensory receptors ; filters out less important information
259
Phasic receptors
adapt very quickly and specialize in the perception of changes in stimuli
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Tonic receptors
adapt more slowly; the length of time required for tonic receptors to stop producing action potentials provides information to the nervous system about the intensity of the stimulus
261
Eye
detects patterns of light and transmits this information to the nervous system, ultimately resulting in the perception of vision
262
Cornea
nonvascular and made largely from collagen; it is clear with a refractive index of about 1.4 meaning that that incoming light is actually bent further at the interface of the air and the cornea rather than at the lens; where light first strikes the eye
263
Lens
naturally has a spherical shape, but stiff suspensory ligaments tug on it and tend to flatten it, this allows the shape of the lens to be adjusted according to the focal length needed to ensure that the image produced by a given object will be focused precisely on the retina, rather than behind or in front of it
264
Ciliary muscle
suspensory ligaments are connected to this muscle and when it contracts the lens becomes more like a sphere bringing its focal point closer to the lens; when the muscle relaxes, the lens flattens, increasing the focal distance
265
Retina
covers the inside of the back (distal portion) of the eye; contains rods and cones
266
Rods
type of photoreceptor that respond to all photons with wavelengths in the visible spectrum (390nm - 700 nm) so they cannot distinguish color
267
Cones
type of photoreceptor; 3 different cones each with a different pighment that is stimulated by a slightly different spectrum of wavelengths ; able to distinguish colors
268
Rhodopsin
pigment in rod cells
269
Fovea
small point on the retina containing mostly cones; point on the retina where vision is most acute
270
Iris
the colored portion of they eye that creates the opening called the pupil
271
Bipolar cells
receive signals from their associated photoreceptors (vertical information) and also affected by signals from horizontal cells
272
Horizontal cells
provide horizontal information from photoreceptors at the edge of the bipolar cell's receptive field
273
Pathway of vision
light-->cornea-->retina (bipolar cells --> photoreceptors) --> optic nerve -->LGN --> primary visual cortex--> ventral pathway and dorsal pathway
274
Optic nerve
leaves the eye to convey visual information to the brain; some of the axons from each eye cross to the opposite side of the brain
275
Lateral genticulate nucleus (LGN)
part of the thalamus; preserves the visual map created by the ganglion cells and projects this information to the primary visual cortex
276
Primary visual cortex
located in the occipital lobe
277
Pigments
undergo a chemical change when one of their electrons is struck by a single photon
278
Rod cell hit with light
retinal isomerizes causing the membrane of the rod cell to become less permeable to sodium ions which causes it to hyperpolarize
279
Retinal
prosthetic group of rhodopsin
280
Ventral "what" pathway
travels from primary visual cortex to the temporal lobe toward the base of the brain and is involved in object recognition
281
Dorsal "where" pathway
travels from primary visual cortex to the parietal cortex and is more involved in perceiving the location of objects
282
Ear
transforms sound from waves of pressure in the air into physical vibrations into electrical signals; divided into outer ear, middle ear, and inner ear
283
Middle Ear
contains 3 small bones: the malleus, incus, and stapes which act as a lever system and vibrate from the tymapnic membrane; these physical vibrations are conveyed to the oval window
284
Cochlea
part of inner ear; basically detects sound, contains the organ of Corti
285
organ of Corti
located on the cochlea's basilar membrane; as the wave moves through the cochlea the organ of Corti vibrates causing movement of its hair cells
286
Hair cells
their movement is transduced into neural signals that are sent to the brain
287
Semicircular canals
part of inner ear; detect orientation and movement of the head (vestibular system)
288
Otilith organs
involved in the vestibular system primarily tilting and linear acceleration
289
Vestibular system
responsible for detecting changes in position and signaling the body to make necessary adjustments to maintain balance
290
Kinesthetic sense
contributes to the awareness of the body's location and movement, to give the individual an overall sensation of the body
291
Processing of auditory information
movement hair cells release neurotransmitter to cochlear nerve --> cochlear nuclei--> inferior colliculus ---> medial genticulate nucleus --> auditory cortex
292
Medial genticulate nucleus
part of the thalamus; auditory information passes through this area on its way to a higher cortical area)
293
Auditory cortex
in the temporal lobe; receives information from the thalamus and is where the detection of complex features of auditory information such as patterns take place
294
Spatial organization of hair cells along the organ of Corti
hair cells in the part of the basilar membrane that is closes to the stapes and therefore the most stif, respond best to higher frequencies; the opposite is true for hair cells that are farther away from the base of the ear, in the more flexible portion of the basilar membrane
295
5 primary taste sensations
bitter, sour, salty, sweet, and umami (savory); all taste sensations are a combination of these five
296
Olfactory nerve
axons of the olfactory chemoreceptors ; the binding of chemicals to G protein coupled receptors on the chemoreceptors triggers and action potential that is transmitted to the olfactory bulb
297
Olfactory bulb
recieves inupt from olfactory nerve and projects directly to the pyriform/olfactory cortex; also projects directly to the amygdala and hippocampus in the temporal lobe
298
Pyriform/olfactory cortex
in temporal lobe; conveys olfactory information to the orbitofrontal cortex where it is integrated with other sensory information
299
Olfactory pathway
olfactory nerve -->> olfactory bulb --> pyriform cortex (note that it does not pass through the thalamus before reaching higher cortical areas)
300
Pheromones
not perceived consciously; thought to exert a subconscious influence on behaviors related structures of amygdala and hypothalamus such as aggression and sexual behavior; unclear whether they affect human behavior
301
Contributors to resting potential of neuron
electrochemcial gradients of potassium, sodium and chloride (chloride contributes the least)
302
Motor and sensory neuron innervation in spine
sensory: dorsal roots; motor: ventral roots
303
Acetylcholinesterase
degrades acetylcholine in synapse
304
Light passage through the eye
Cornea --> aqueous humor --> lens --> vitreous humor --> retina
305
Lysogenic or lysic for phages to survive in body during a bacterial infection
lysogenic as the host cell would not be destroyed which would cause inflammation and attraction of immune cells at the site of cell death
306
Exocrine glands
release enzymes to the external environment through ducts ie. sudiferous (sweat), sebaceous (oil), mucous and digestive glands
307
Endocrine glands
release hormones directly into the bloodstream
308
3 chemistry types of hormones
peptide, steroid, and tyrosine derivatives
309
Peptide hormones
polar, move alone through bloodstream, attach to membrane-bound receptors, may be large or small, made in rough ER as preprohormones and then cleaved in ER lumen to prohormone and transported to Golgi
310
Steroid hormones
formed in smooth ER and mitochondria, hydrophobic, require a carrier protein, diffuse through cell membrane to reach their effector in cytosol or nucleus and act at level of transcription
311
Tyrosine derivative hormones
formed in the cytosol or rough ER, not all either water or lipid soluble like peptide and steroid hormones
312
Portal system
shared blood vessels
313
Hormones of posterior pituitary gland
ADH and oxytocin
314
Antidiuretic hormone (ADH)
vasopressin; small peptide hormone which causes the collecting ducts of the kidney to become permeable to water causing reabsorption of water from the collecting tubule, increases blood pressure
315
Oxytocin
small peptide hormone that increases uterine contractions during pregnancy and milk to be ejected from the breasts
316
Anterior pituitary gland
located in brain beneath the hypothalams
317
Posterior pituitary gland
composed mainly of support tissue for nerve endings extending from the hypothalamus
318
Hypothalamus
controls the release of the anterior pituitary hormones with releasing and inhibitory hormones of its own
319
Hormones of anterior pituitary gland
TSH, ACTH, FSH, LH, HGH, Prolactin
320
Thyroid-stimulating hormone (TSH)
peptide that stimulates the thyroid to release T3 and T4 via cAMP, increases thyroid cell size, number, and rate of secretion of T3/T4
321
Adrenocorticotropic hormone (ACTH)
peptide that stimulates the adrenal cortex to release glucocorticoids via cAMP, stimulated by stress
322
Human growth factor (HGF)
somatotropin; peptide that stimulates growth in almost all cells of the body by increasing rate of mitosis, cell size, rate of protein synthesis, mobilizing fat stores, increasing the use of fatty acids for energy and decreasing use of glucose; also increases transcription/translation and decreases breakdown of protein and AAs
323
Prolactin
peptide that promotes lactation (milk production) by the breasts; act of suckling stimulates hypothalamus which stimulates anterior pituitary gland to release prolactin
324
Parathyroid hormone (PTH)
peptide that increases blood calcium by increasing osteocyte absorption of calcium, stimulating proliferation of osteoclasts, increases reabsorption of calcium and phosphate from bone, increase renal reabsorption of calcium and excretion of phosphate, increase absorption of calcium and phosphate from gut
325
Basal metabolic rate
resting metabolic rate, amount of energy expended at rest in one day and is commonly measured as rate of oxygen consumption ; determined by heart rate and muscle mass
326
T3/T4
released by thyroid; lipid soluble tyrosine derivatives, regulated by TSH, help determine the basal metabolic rate
327
Hormones of thyroid
calcitonin and T3/T4
328
Calcitonin
large peptide hormone that slightly decreases blood calcium by decreasing osteoclast activity and number
329
Adrenal glands
located on top of the kidneys, separated into adrenal cortex and adrenal medulla
330
Adrenal cortex
outside portion of adrenal gland and only secretes sterioid hormones
331
Hormones of adrenal cortex
mineralocorticoids and glucocorticoids
332
Mineralocorticoids
steroid, affects the electrolyte balance in the bloodstream, aldosterone
333
Glucocorticoids
steroid, increase blood glucose concentration and have an even greater effect on fat and protein metabolism, cortisol
334
Aldosterone
mineralocorticoid that acts in the distal convoluted tubule and the collecting ducts to increase sodium and chloride reabsorption and K and H secretion; Na reabsorption drives increased water reabsoprtion through aquaporins which leads to an increase in blood pressure
335
Cortisol
glucocorticoid that increases blood glucose levels by stimulating gluconeogenesis in the liver, mobilize fatty acids from fat cells to be used for energy and causes a moderate decrease in use of glucose by cells. stimulates protein degradation in nonhepatic cells to create AA which serve as carbon sources for gluconoegenesis; diminish capacity of immune system
336
Epinephrine/adrenaline (as a hormone)
catecholamine, tyrosine derivative, similar effect to SNS but effects last longer
337
Norepinephrine/noadrenaline (as a hormone)
catecholamine, tyrosine derivative, similar effect to Parasympathetic nervous system but effects last longer
338
Hormones released by adrenal medulla
epinephrine and norepinephrine
339
Pancreas
acts as both an endocrine and exocrine gland
340
Hormones released by pancreas
beta cells release insulin, alpha cells release glucagon, delta cells release somatostatin
341
Somatostatin
inhibits both insulin and glucagon; may be to extend the period of time over which nutrients are absorbed
342
Insulin
peptide hormone, released when blood levels of carbohydrates or proteins are high; carbohydrates are stored as glycogen in the liver and muscle, fat is stored in adipose tissue and AAs are taken up by the cells of the body and made into proteins --> lower blood glucose levels as cells become more permeable to glucose by opening membrane bound glucose transporter
343
Glucagon
peptide hormone,stimulates glycogenolysis (breakdown of glycogen) and gluceogenesis in the liver, acts via cAMP, breaks down adipose tissue increasing fatty acid levels in the blood, net effect is to raise blood glucose levels
344
Tropic hormones
released from one gland and cause downstream release of other hormones from their target endocrine glands
345
Blood chemistry hormones
control the concentrations of sodium, calcium and glucose in the bloodstream
346
Osmolarity in bloodstream
determined by sodium concentrations
347
Luteinizing hormone (LH)
stimulate Leydig cells which leads to ovulation and estrogen or testosterone release
348
Follicle stimulating hormone (FSH)
stimulates sertoli cells which promotes growth of follicles or sperm production in males; stimulates the growth of granulosa cells around primary oocyte in females
349
Gonads
organs involved in the the production of gametes
350
Male gonads
testes
351
Seminiferous tubules
a set of long, twisted tubes in the testes that are lined by Sertoli cells and spermatogonia, site of production of sperm
352
Sertoli cells
surround and nurture the spermatocyte and spermatids ; secrete inhibin that acts on the pituitary gland to inhibit FSH secretion
353
Leydig cells
located in the interstitium between the tubules, release testosterone in males; estrogen
354
Androgen
male sex hormone ie. testosterone
355
Testosterone
stimulates the germ cells to differentiate into sperm, development of secondary sex characteristics, puberty, closure of the epiphyses of long bones
356
Structure of sperm
head/acrosome, midpiece/mitochondria, and tail
357
Acrosome
contains lysosome-like enzymes for penetrating the egg during fertilization
358
Epididymis
where sperm stays to mature after it is released from the semineferous tubules
359
Movement of sperm during ejaculation
moves through vas deferens into the urethra and out the penis
360
Semen
complete mixture of spermatozoa and fluid that leaves the penis upon ejaculation; composed of fluid from seminal vesicles, prostate and bulbourethral glands/Cowper's glands
361
Capacitation
process by which spermatozoa become activated for fertilization which takes place in the vagina
362
Granulosa cells
secrete a viscous substance around the egg called the zona pellucida; convert androgen to estradiol (a type of estrogen)
363
Luteal surge
just before ovulation, the estradiol level rises rapidly and causes a dramatic increase in LH secretion; resulst from a positive feedback loop where rising estrogen levels increase LH levels which increase estrogen; causes ovulation
364
Ovulation
the bursting of the follicle and release of the egg in to the body cavity
365
Fallopian/uterine tube
where the egg remains after ovulation
366
Corpus luteum
remaining portion of the follicle that is left behind after ovulation; secretes estradiol and progesteron throughout pregnancy or in case of no pregnancy for 2 weeks until it degrades into the corpus albicans
367
Ovarian cycle
follicular phase and luteal phase
368
Follicular phase of ovarian cycle
begins with the development of the follicle and ends at ovulation; menstruation (beginning)and proliferation phase
369
Luteal phase of ovarian cycle
begins with ovulation and ends with the degeneration of the corpus luteum into the corpus albicans (menstruation end)
370
Progesterone
acts as a maintenance hormone for the uterus
371
Corpus albicans
no longer able to secrete progesterone to maintain the uterine wall and so the uterine wall sloughs off and produces menstruation
372
Cortical reaction
entry of the sperm causes the cortical reaction which prevents other sperm from fertilizing the same egg
373
Cleavage
begins when the zygote is still in the Fallopian tube, the zygote goes through many cycles of mitosis; the embryo at this stage does not grow
374
Morula
when the zygote is comprised of 16 or more cells
375
Totipotent
have the potential to express any of their genes; can become any cell, placenta or embryo
376
Blastocyst
a mostly hollow ball that is filled with fluid and has a small cell mass on one side, forms after morula continues to divide;
377
Implantation
when the blastocyst lodges in the uterus, considered pregnant
378
Placenta
forms when the outer cells of the blastocyst implant in the uterine wall and fuse with the uterine tissue
379
Stem cells
pluripotent cells meaning that it has the abilitiy to develop into most of the types of cells in the human body depending on its position in the mass/ any one of the initial 3 germ layers
380
Human chorionic gonadotropin (HCG)
secreted by placenta after implantation; prevents the degeneration of the corpus luteum and maintains its secretion of estrogen and progesterone; presence in blood or fluid is outward sign of pregnancy
381
Determination
the process where a cell becomes committed to a specialized developmental path
382
Differentiation
the specialization that occurs at the end of development, forming a specialized tissue cell
383
Multipotent stem cells
can regenerate as needed; present in systems that experience injury (skin, liver, blood); replace cells of a particular lineage
384
Gastrulation
formation of the gastrula 3 weeks after fertilization; 3 primary germ layers are formed
385
Ectoderm
epidermis of skin, nervous system, sense organs
386
Mesoderm
skeleton, muscles, blood vessels, heart, blood, gonads, kidneys
387
Endoderm
lining of digestive and respiratory tracts, liver, pancreas, thymus, thyroid
388
Neurulation
gastrula develops into a neural
389
Induction (embryology)
occurs when one cell type affects the direction of differentiation of another cell type
390
Formation of neural plate
through induction, the notochord (made from mesoderm) causes overlying ectoderm to thicken and form the neural plate; the notochord eventually degenerates while a neural tube forms from the neural plate to become the spinal cord, brain, and most of the nervous system
391
Neural crest
cells of the ectoderm that close to the neural tube; function mostly as accessory cells to the nervous system such as Schwann cells
392
Apoptosis
programmed cell death; essential for development; damaged cells may undergo as well
393
Senescence
process by which cells stop proliferating in response to environmental stressors and are are ultimately cleared away by immune cells; implicated in the aging process
394
Prenatal development
development that occurs before birth and begins with development of the embryo
395
Teratogens
harmful substances to an embryo; particularly harmful due to fast growth of multiple structures
396
Order of development for embryo
morula --> blastula --> gastrula --> neurula; 1st trimester: development; 2nd trimester: growth and development; 3rd trimester: growth
397
Motor development of infant
direction of development is from head to toe (a cephalocaudal pattern) and from the midline of the body to the periphery (proximodistal pattern)
398
Puberty
biological changes that ultimately lead to sexual maturity
399
Parturition
time of birth; brain is not fully developed
400
Menopause
period in woman's life when period stops; decreased estrogen
401
Estrogen and bone strength
stimulates osteoblastic activity
402
Panting
increases respiration rate, bringing more water into the upper part of the respiratory tree that can then evaporate
403
Nasal cavity
the space inside the nose that acts to filter, moisten, and warm incoming air
404
Nasal hairs
near front of naval cavity and traps large dust particles
405
Mucus
secreted by goblet cells which traps smaller dust particles that were able to bypass the coarse nasal hair and also moistens the air
406
Cilia in nasal cavity
move mucus and dust back toward the pharynx to be removed by spitting or swallowing
407
Pharynx
throat; functions as a passageway for food and air
408
Larynx
contains the vocal chords
409
Epiglottis
cartilaginous structure that rises to block the opening of the trachea during swallowing, preventing the entry of food into the airway
410
Trachea
composed of ringed cartilage covered by ciliated mucous cells which collect particulate matter and usher it back out toward the pharynx
411
Bronchi
2 split from the trachea; right/left
412
Bronchioles
make up the bronchi; terminate in grape-like clusters called alveolar sacs which are composed of aveoli
413
Alveoli
oxygen diffuses from each alveolus into an adjacent capillary where it is picked up by red blood cells; the red blood cells release carbon dioxide which diffuses into the alveolus and is expelled upon exhalation
414
Medulla oblongota and respiration
signals the diaphragm to contract
415
Diaphragm
thin sheet of skeletal muscle that is innervated by the phrenic nerve; dome shaped in a relaxed state but flattens upon contraction, expanding the chest cavity
416
Intercostal muscle
rib muscles' also help to expand the chest cavity
417
Surfactant
alveoli contain a type of cell that produces surfactant, a a material composed of amphipathic phospholipids; coats the alveolar surface and breaks up the intermolecular forces between water molecules, reducing surface tension of water on the inner surface of alveoli which assists the expansion of the lungs
418
Respiration - differential partial pressures
high partial pressure of oxygen in the alveoli compared to the low partial pressure in the deoxygenated blood in adjacent capillaries; blood has a high partial pressure of carbon dioxide compared to that of the alveoli
419
Fick's law
the rate of diffusion is directly proportional to the surface area and differential partial pressure across the membrane, and is inversely proportional to the thickness of the membrane across which diffusion occurs
420
Henry's Law
states that the amount of gas that can be dissolved in solution is directly proportional to the partial pressure of a gas in equilibrium with the liquid
421
Hemoglobin
composed of 4 polypeptide subunits each with a single heme cofactor; the heme cofactor is an organic molecule with an iron atom at its center; each of the 4 iron atoms in hemoglobin binds an oxygen molecule which accelerates the oxygenation of the other heme groups (cooperativity)
422
Rightward shift of the oxygen dissociation curve
occurs in response to an increase in carbon dioxide pressure, hydrogen ion concentration, or temperature (heat released during metabolism which requires O2); reflects hemoglobin's lower affinity for oxygen
423
Bohr shift
when the rightward shift of the oxygen dissociation curve is due to CO2 ( increasing hydrogen ion concentration and CO2 itself)
424
2,3-DPG/BPG
chemical found in red blood cells that shifts oxygen dissociation curve rightward by binding to deoxygenated hemoglobin and decresasing its affinity to oxygen; increaes in response to low oxygen environments such as high altitudes
425
Carbonic anhydrase
catalyzes the formation of bicarbonate (and hydrogen ions) from carbon dioxide; present in red blood cells but not plasma
426
Chloride shift
entry/leaving of chloride ions from erythrocyte offsets the buildup of hydrogen ions
427
Chloride shift in tissues
chloride ions flow into erythrocyte as bicarbonate follows its concentration gradient from erythrocyte to plasma
428
Chloride shift in lungs
chloride ions flow out of erthrocyte as bicarbonate follows its concentration gradient from plasma into erythrocyte
429
Nervous system sensitivity to changes in CO2 and O2
much more sensitive to changes in carbon dioxide which are monitored by central chemoreceptors
430
pH control through breathing
in the case of acidosis, the body compensates by increasing the breathing rate, thereby expelling carbon dioxide and raising the pH of the blood
431
Blood
connective tissue (contains cell and a matrix); travels throughout the body via the cardiovascular system; made of 3 components: plasma, red blood cells, and buffy coat (white blood cells)
432
Plasma
contains the matrix of the blood, which includes water, ions, urea, ammonia, proteins, and other organic/inorganic compounds
433
Albumin
protein found in blood that transports fatty acids and steroids and help regulate the osmotic pressure of blood, facilitating transfer of substances across capillary walls
434
Serum
plasma from which the clotting protein fibrinogen has been removed
435
Plasma proteins
albumin, fibrinogen and most others are formed in the liver; acts as a source of amino acids for tissue protein replacement
436
Hematocrit
the percentage of volume of red blood cells; typically 35 - 50% and greater in men than women
437
Leukocytes
white blood cells; contain organelles but not hemoglobin; function is to protect the body from foreign invaders
438
Erythrocytes
red blood cells; have no organelles, no nuclei, and do not undergo mitosis; they are disc shaped and there main function is to transport oyxgen and carbon dioxide
439
Granular leukocytes/granulocytes
live for a very short time because they function nonspecifically against all infective agents; multiply quickly against any infection and then die once the infection is gone; neutrophils, eosinophil, basophil
440
Agranular leukocytes/agranulocytes
live for a longer time, and work against specific agents of infection; hang around after in case the infection returns; include monocytes, lymphocytes, and megakaryocytes
441
Platelets
small portions of membrane-bound cytoplasm torn from megakaryocytes; do not have nuclei; contain actin and myosin, mitochondria, golgi and ER; capable of making prostaglandins and other important enzymes; function in coagulation
442
Coagulation
functions to minimize blood loss and facilitate healing when blood vessels are damaged; most important step is the polymerization of the plasma protein fibrinogen to form fibrin threads that attach to the platelets and form a tight plug
443
Closed circulatory system
contains no opening for the blood to leave the vessels
444
Systemic circulation
directs oxygenated blood to the tissues and then returns deoxygenated blood to the heart
445
Movement of blood in systemic circulation
left ventricle --> aorta --> smaller arteries --> arterioles --> tissue capillaries --> venules ---> veins --> superior/inferior venae cavae --> right atrium
446
Pulmonary system
transports blood to the lungs for oxygenation
447
Movement of blood in pulmonary system
right atrium --> right ventricle --> pulmonary arteries --> arterioles --> lung capillaries --> venules --> veins --> pulmonary veins --> left atrium
448
Pulmonary arteries
only arteries in the adult body that carry deoxygenated blood
449
Sinoatrial (SA) node
a group of specialized cardiac muscle cells located in the right atrium; autorhythmic spreading its contractions to the surrounding cardiac muscles via electrical synapses formed by gap junctions; pace of SA node faster than normal heart beats
450
Vaguns nerve
innervates the SA node slowing the contractions of heart to produce the typical resting heart rate
451
Atrioventricular (AV) node
located in the interatrial septum (wall of cardiac muscle between the atria); slower to depolarize than the SA node creating a delay which allows the atria to finish their contraction and squeeze their contents into the ventricles before the ventricles to contract
452
Purkinje fibers (in heart)
action potential then branches out through the ventricular walls via these conductive fibers which allows for a more unified and stronger contraction
453
bundle of His
located in the wall separating the ventricles; from the AV node, action potential moves down conductive fibers in the bundle of His
454
Four methods by which materials cross capillary walls
pinocytosis, diffusion or transport through capillary cell membranes, fenestrations, movement through the space between the cells
455
Fenestrations
movement through pores in the cells
456
Systolic pressure
highest pressure and is measured in the arteries during systole
457
Dialostic pressure
pressure during the relaxation of the ventricles and filling of the atria and is the lowest pressure in the cardiac cycle
458
Total peripheral resistance
the overall resistance of the entire systemic circulatory; changes in this resistance are primarily achieved through constriction or dilation of smooth muscle surrounding arterioles which are the blood vessels that contribute the most to peripheral resistance
459
Baroreceptor reflex
regulates blood pressure by altering both cardiac output and blood vessel resistance to flow
460
Baroreceptor
type of mechanoreceptor located within arteries detect changes in blood pressure ; respond by signaling centers in the brainstem to alter sympathetic and parasympathetic nervous system output to the heart and blood vessels
461
Renin-angiotensin-aldosterone system
regulates blood pressure through the regulation of plasma volume; activated when mechanoreceptors in arteries leading to the kidneys detect a decrease in blood pressure; a cascade of enzymatic effects triggered by the secretion of renin leads to increased intake and retention of water which increases plasma volume
462
Velocity of arteries and veins
greatest in the arteries where cross-sectional area is smallest and velocity is lowest in the capillaries where cross-sectional area is greatest
463
Precapillary sphincters
regulate the flow of blood into capillary beds according to the metabolic needs of the tissues
464
Osmotic pressure
pulling pressures of solutes in solutions that leads to the diffusion of solvent across a membrane; encourages the flow of fluid from the tissues into the capillaries; relatively constant
465
Hydrostatic pressure
encourages the flow of fluid into the interstitium; higher in arteries, lower in veins
466
Lymphatic system
open system (fluid enters at one end and leaves at the other); drainage and immune response
467
Innate immunity
quick and non-specific providing a generalized protection from most intruding organisms and toxins
468
Acquired/adaptive immunity
develops more slowly and only after the body has experienced the initial attack
469
Examples of innate immunity
skin, stomach acid/digestive enzymes, phagoctyic cells such as neutrophils and macrophages, and chemicals in the blood
470
Inflammation
functions to "wall-off" affected tissue and local lymph vessels from the rest of the body, impeding the spread of infection; dilation of blood vessels, increased permeability of capillaries, swelling of tissue cells, and migration of granulocytes and macrophages to inflamed area
471
Causative agents of inflammation
histamine, prostaglandins, and lymphokines
472
Macrophages
involved in innate immune respons; infectious agents that enter the body are first attacked by these cells; die after engulfing bacteria
473
Eosinophils
work mainly against parasitic infections
474
Basophils
release many of the chemicals of the inflammation reaction
475
Types of acquired ammunity
B-cell immunity and T-cell immunity
476
Plasma cells
can survive for decades or even a lifetime; synthesize free antibodies and release them into the blood during primary response
477
Memory B-cells
long-lived; in case of reinfection these cells can be called upon to synthesize antibodies
478
Primary response for BCR
the immune response that results from the first exposure to an antigen which requires 20 days to reach full potential, the BCR recognizes the appropriate antigen under the right conditions; when this happens the B-lymphocyte differentiates (with help of helper T cells) into plasma cells and memory B-cells
479
B-lymphocytes
differentiate and mature in the adult bone marrow and the fetal liver; makes a single type of antibody/immunoglobin which can recognize and bind to a particular antigen
480
B-cell receptor (BCR)
initially a B-lymphocyte displays its particular antibody on its membrane and the antibody is called a BCR
481
Antigenic determinant
the portion of the antibody that binds to an antigen which is highly specific for that antigen
482
Secondary response
reinfection in which memory b-cells fight against
483
Antibody function during primary response
(produced by plasma cells); 1. mark antigen for phagocytosis by macrophages and natural killer cells 2. bind and perforate the antigen bearing cell 3. cause the antigenic substances to agglutinate (stick together) or precipitate 4. attach their bases to mast cells which release histamine and other chemicals
484
T-lymphocytes
made in the bone marrow and mature in the thymus; has an antibody-like protein at its surface that recognizes antigens termed the T-cell receptor (TCR); never make free antibodies
485
TCR during primary immune response
when a TCR recognizes the appropriate antigen, T-lymphocytes differentiate into helper T-cells, memory T-cells, suppressor T-cells, and killer T-cells
486
Helper T cells
assist in activating B-lymphocytes (to differentiate), also activate other types of T-lymphocytes
487
Killer T cells
bind to the antigen-carrying cell and release perforin, a protein that punctures the antigen-carrying cell; can attack many cells because they do not phagocytize their victims and not destroyed when they kill pathogens
488
Major histocompatibility complex (MHC) molecules
all human cells with nuclei express these molecules on their cell surface; their function is to display antigens for recognition
489
MHC class I molecules
display antigens derived from intracellular pathogens; since all cells can be infected by these pathogens, all nucleated cells have these molecules
490
Endogeneous pathway
the process by which intracellular antigens are processed and displayed on the cell surface
491
MHC class II molecules
display antigens derived from extracellular pathogens; only displayed by phagocytic cells
492
Activtation of B and T cells
require both signal 1 and signal 2; protects against an autoimmune response
493
Signal 1
provided when the BCR or TCR recognizes its appropriate antigen
494
Signal 2
B-cells and T-cells receive it when there is an active infection
495
Autoimmune disease
where a hyperactive immune system attacks the body's own tissues; caused from too little regulation and can be caused from a failure of clonal selection
496
Clonal selection
only certain B and T cells are permitted to mature and proliferation (fully funciontal ones)
497
Positive (clonal) selection
when a b or t cell cannot recognize the MHC molecule
498
Negative (clonal) selection
when the b or t cells respond too strongly to MHC molecules with self-antigens
499
Self-antigens
antigens from endogenous normal proteins
500
Components of digestive tract
mouth --> esophagus --> stomach --> small intestine --> large intestine --> anus
501
Ingestion
the process of taking in food through the mouth; chewing and chemcial breakdown by a-amylase contained in saliva
502
Bolus
the clump of chewed food
503
Peristalsis
contraction of the smooth muscle in the digestive tract which creates a wave motion that pushes along the partially digested food
504
Saliva
acts as lubrication for the food, helping it move down the digestive tract, also contains a-amylase
505
Components of stomach
fundus, body, pylorus; serves to store food
506
Fundus
collects excess gas produced by digestion and can expand to store food ingested during a large meal prior to digestion
507
Body (of stomach)
primary site of digestion within the stomach
508
Pylorus
acts to prevent the passage of undigested food into the small intestines
509
Sphincter
ring of muscle that is normally contracted so that there is no opening at its center
510
Chyme
fiid reduced to a semi-fluid mass
511
Gastric juice
a combination of acid, enzymes, and hormones released by cells in the lining of the stomach; low pH contributes to protein digestion by denaturing proteins and also helps kil ingested bacteria
512
4 major cell types of the stomach
mucous cells, chief/peptic cells, parietal/oxyntic cells and G cells
513
Mucous cells
line the the stomach wall and the necks of the exocrine glands so that food can slide along surface of the the stomach wall without causing damage; also protects the eptihelial lining of the stomach wall from the acidic environment; composed of sticky glycoproteins and electrolytes
514
Chief/peptic cells
found in the exocrine cglands and secrete pepsinogen
515
Pepsinogen
zymogen precursorr to pepsin; activated by low pH of the stomach
516
Pepsin
protein digestion
517
Zymogen
proenzymes; inactivave precursors to enzymes that can be activated to become functional enzymes
518
G cells
secrete gastrin; activated by presence of polypeptides in stomach, stomach distension and input from parasympathetic nervous system
519
Gastrin
a large peptide hormone that stimulates parietal cells to secrete HCl
520
Parietal cells
found in exocrine gland of stomach; secrete HCl into the lumen through active transport which requires large input of energy
521
Components of small intestine
duodenum --> jejunum --> ileum
522
Duodenum
most digestion occurs in the duodenum
523
Jejunum and ileum
most absorbtion occurs here
524
Villi
increase the surface area of the intestinal wall allowing for greater digestion and absorption
525
Lacteal
the lympathic vessels of the small intestine which absorb fats (within a villus)
526
Microvilli
increase the surface area even further
527
Enterocytes
intestinal epithelial cells
528
Goblet cells
secrete mucus to lubricate the small intestine and help protect the brush border from mechanical and chemical damage
529
Brush border
contains membrane bound digestive enzymes
530
Pancreas
aids the digestive process (and regulates metabolism); secretes bicarbonate ion to regulate hydrochloric acid released from the stomach; creates enzymes (released as zymogens) that aid in the digestive processes in the small intestine
531
Major enzymes of pancrease
trypsin, chymotripsin, pancreate amylase, lipase, ribonuclease, deoxyribonuclease
532
Trypsin/chymotrypsin
degrade proteins into small polypeptides
533
Lipase
degrade fate specifically trigylcerides
534
Bile
produced in the liver and stored in the gall bladder; ultimately released into the small intestine to emsulfiy fat which increases its surface area so that lipase can degrade it into mainly fatty acids and monoglycerides
535
Components of large intestine
ascending colon, transverse colon, descending colon, sigmoid colon, and rectum
536
Function of large intestine
water and electrolyte absorption; also contains a variety of bacterial flora which live off of partially digestive food and in turn produce vitamin K, B12, thiamin and riboflavin
537
Feces
75% water, remaining solid mass is 30% dead bacteria, 10-20% fat, 10-20% inorganic matter, 2-3% protein and 30% roughage (ie. cellulose) and undigested matter
538
Rectum
acts as a storage receptacle for feces until the waste is eliminated through the anus
539
Enteric nervous system
consists of a large network of neurons surrounding the digestive organs, helping to regulate processes such as smooth muscle contraction (peristalsis), fluid exchange, blood flow to the digestive organs and hormone release
540
Molecular digestion of carbohydrates
large polysacchardies broken down by amylase in intestinal lumen --> small polyaccharides broken down by brush border enzymes --> broken down molecules enter via secondary transport with sodium --> facilitated fiffusion from enterocyte to blood
541
Molecular digestion of proteins
trypsin and chmotrypsin break down proteins into small polypeptides --> brush border enzymes break these down in to amino acids --> amino acids enter via co-transort with Na+, intracellular enterocyte enzymes further degrade, and then amino acids enter blood via facilitated diffusion/ or active transport
542
Molecualr digestion of fats
similar to digestion of proteins and carbohydrates but fats/trigylcerides emulsifty into micelles which then diffuse through enterocyte membrane where they are converted back into trigylcerides in the smoothe ER and the nleave through lacteal (NOT blood)
543
Albumin
protein that carries fatty acid molecules in the blood
544
Metabolic functions of liver
carbohydrate metabolism (gluconeogenesis), fat metabolism, protein metabolism, detoxification
545
Storage functions of liver
blood storage, glycogen storage, vitamin storage
546
Immune functions of liver
blood filtration, erythrocyte destruction
547
Functions of muscle
body movement, stabilization of body position, movement of substances through the body, and generating heat to maintain body temperature
548
Skeletal muscle
type of striated muscle; voluntary muscle innervated by the somatic nervous system; moves the body, involved in thermoregulation and movement of fluids in cardiovascular and lymphatic systems
549
Tendon
connective tissue connecting muscle to bone
550
Ligament
connective tissue connecting bone to bone
551
Peripheral circulatory assistance
contraction of skeletal muscle helps squeeze blood and lymph through their respective vessels, aiding circulation
552
Shivering reflex
the rapid contraction or shaking of skeletal muscle to warm the body; controlled by the hypothalamus
553
Sarcomere
smallest functional unit of the contractile apparatus in skeletal muscle; composed of thick filaments made of myosin and thin filaments made of actin
554
Z line
separates one sarcomere from the next and is where actin filaments attach
555
I Band
area containing only actin
556
H zone
area containing only myosin
557
A band
area where myosin and actin is present
558
M line
midline of the myosin fibers
559
Sarcoplasmic reticulum
specialized endoplasmic reticulum filled with calcium ions
