Psychobiology Summary - Biological Psychology (400156-B-6) PDF

Summary Psychobiology - Biological Psychology (400156-B-6) written by curtalaura The Marketplace to Buy and Sell your Study Material At Stuvia, you will find the best notes, summaries, f...

Summary Psychobiology - Biological Psychology (400156-B-6) written by curtalaura The Marketplace to Buy and Sell your Study Material At Stuvia, you will find the best notes, summaries, flashcards & other study material. Search for your school or uni and find the study material you need. www.stuvia.com Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Biological psychology this summary is based on lecture slides, the book Psychobiology by Chris Chandler, explanations received during class and other resources that help explain and remember certain concepts better 1 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Evolution & genetics - Darwin proposed that all organisms are related and share a common ancestor; he attempted to explain how modern organisms are successful adaptions of previous generations- these modifications occurring in the process of natural selection (=those organisms that possess beneficial characteristics are more likely to survive and reproduce) via reproduction, these characteristics are passed on to the next generation; organisms that are not ideally equipped to interact with their environment stand a smaller chance of adapting to that environment, limiting their opportunity to survive and reproduce (survival of the fittest) - with natural selection, there is no specific plan, the environment is the influence, and evolution is a relatively slow process; genetic modification is an even quicker form of selection, in which genes are added or deleted for the benefit of the organism or at least mankind - evidence for the theory of evolution: biogeography fossil record (looking at the different geological layers reveals changing fossils and these changes permit the palaeontologist to chart the evolution of species) structural similarity (across species there are comparative similarities. In evolutionary terms, these have developed from a common ancestor) embryology (by comparing the development of embryos, it was revealed that there are similar stages in utero across species) molecular biology - mammals evolved from reptiles about 10 million years ago; they were able to feed their offspring using mammary glands (breastfeeding); they further evolved and developed the ability to produce and internal environment suitable for the protection and development of their offspring – pregnancy; the development in utero (in the uterus) of new living organism permits greater safety and protection from harsh environments; however, there are still many challenges to the foetus (for example alcohol) - in the categories of mammals, humans are arguably the most advanced form of life compared to the orders of primates; included in the primates are the apes, including the gibbons, orangutans, gorillas, and chimpanzees; we don’t come from chimpanzees, though - humans are members of the family Hominines; within this family, there are two genera: Australopithecus and Homo; we come from the Homo group – humans are Homo sapiens - humans have a relative, Homo erectus, that is now extinct; the Homo species emerged about 2 million years ago and might come from one species of Australopithecus. - it is suggested that the Homo sapiens can all be traced back to Africa; about 200,000 years ago Homo sapiens appeared and about 50,000 years ago modern humans began 2 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material to migrate out of Africa- this is the ‘’Out of Africa’’ hypothesis- people moved from the African plains in search of resources; the environmental pressures have therefore shaped modern humans but while we look different and come from different environments, we are all the same species; the increase in brain volume happened before the Homo genus arrived, possibly driven by the increased use of tools - human genes are not that different from those of our close relatives-the chimpanzee and the bonobo; the differences are argued to be due to changes in transcription and translation of the genetic codes; we both have opposable thumbs, but ours are more helpful in manipulating objects; the biggest and most important difference is the brain; the human brain has evolved over tens of millions of years to be the most powerful organ in the natural world and now we can look at its genetic basis: there are important changes in the protein sequences in the human genome, together with duplication and deletion of genes, and further changes in non-coding regions of the genome that are involved in gene expression; humans have, for example, lost some genes for olfactory receptors (other animals have big brains too, but they are nowhere near as complex as the human brain) - the brain itself is an evolutionary development of the vertebrate’s spine; the big difference in brains comes when we look at more recent adaptions of the brain, most notably the cerebrum, which is the most developed part of the human brain, and more developed compared to other species; the human brain has more convolutions (sulci), hence conferring a greater volume to the cortex; in terms of being human, the cortex is the main brain difference; neurons and communication is the same, but architecture and function of cortex are uniquely human y-chromosomal Adam- the most recent common ancestor from whom all currently living people are descended on the father’s side mitochondrial Eve- the most recent woman from whom all living humans are descended matrilineally through transmission of mitochondrial DNA - traits become more common based on a few key steps: variation heritability struggle for existence survival and reproductive rates - we can see evolution in real-time in experiments made with antibiotics and how bacteria learns to adapt to environments with high concentration of antibiotic From evolution to genetics chromosome: a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes gene: a distinct sequence of nucleotides forming part of a chromosome nucleotides: they form the basic structural unit of nucleic acids such as DNA 3 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - in behavioural genetics, there are two subtypes of heritable characteristics or traits: qualitative quantitative qualitative traits are often influenced by a single gene and follow a simple pattern of inheritance - phenotypes are qualitatively different - qualitative traits are typically unaffected by environmental factors; there are several factors that may alter the pattern of inheritance of the characteristic or disorder. - genetic heterogeneity describes an eventuality where clinically similar disorders are caused by mutations in the same gene, result in diverse conditions - sometimes individuals who have inherited disease-associated alleles do not always express the disease completely or partially= penetrance – an allele that does not always lead to the disorder is said to have low penetrance - mosaicism is when not all the cells in the body are genetically identical; this may come about via atypical cellular divisions during early development- such as in Turner’s syndrome (where there is a deletion of the X chromosome from the normal XX genotype in some but not all the cells) - environmental factors, especially those in utero, can give rise to disorders that are similar to those of the genetic origin = phenocopies (example: the rubella virus that can cause deafness as can several genetic defects) multiple genes, some of only modest contribution, influence a quantitative trait; they do not follow simple patterns of inheritance- they are more variable and less predictable than their qualitative counterparts - the phenotype with a quantitative trait is expressed along a continuum (for example, ADHS); phenotypic expression of a quantitative trait, unlike the qualitative traits, is subject to alteration and migration by environmental factors - many disorders are polygenetic; the term quantitative trait loci (QTL) describes how many multiple genes at different locations on the chromosome contribute to the quantitative trait - using linkage analysis, geneticists can investigate QTLs, looking for common occurrences in individuals with a particular characteristic or disorder Mendelian genetics - Mendelian inheritance refers to certain patterns of how traits are passed from parents to offspring; these general patterns were established by the Austrian monk Gregor Mendel, who performed thousands of experiments with pea plants in the 19th century - Mendel noted that only one trait appeared in the first-generation cross – this is referred to as the dominant trait (yellow 4 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material seeds, in this case either Y1 or Y2); the recessive trait (green seeds, as with g1 and g2) was not expressed because it was overridden by the yellow seed trait (in a Y1:g1 seed, the Y1 factor is expressed and the g1 factor is suppressed); in the second generation, green-seeded pea plants were produced (g1:g2) despite not being observed in the first-generation plants; the recessive trait was passed on to the second generation (as with our Y1:g1 plant); the first-generation plants were carriers of the recessive trait (g1), but because it was combined with a dominant trait (Y1) it was not observable => there is a difference between observed traits and genetic traits (what is observed is called the phenotype and what is transmitted genetically is the genotype) Human karyotype - karyotype= an organised set of chromosomes - the karyotype of a human contains 46 chromosomes: 22 identical pairs from mother and father and 1 set of ‘sex’ chromosomes (x and x chromosome for females and x and y chromosome for males) - before birth, the X chromosome of the mother and father ‘battle’ for a place in the DNA; parents bring to the table three X chromosomes, and therefore some have to be deactivated DNA in the cell genome= the whole genetic information of an organism chromosome= a long strand of DNA wound around histones (= protein used to fold the DNA so it doesn’t tangle); it contains many genes gene= part of DNA with an instruction to make proteins telomere= region at the end of the chromosome (protects the DNA during cell division; the more a cell divides, the smaller the telomere gets; people who reach 90 or 100 y.o have longer telomeres) allele= the two alternative forms of a gene found at the same place on a chromosome; they exist only in pairs to produce a phenotypic effect (an observable trait) gene loci= a specific/ fixed position on a chromosome where a particular gene/ genetic market is located 5 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material autosomal dominant trait= patter of inheritance characteristic of some genetic disorders; autosomal means that the gene in question is located on one of the non-sex chromosomes (=autosomes); dominant means that a single copy of the mutated gene (from one parent) is enough to cause the disorder=> a child of a person affected by an autosomal dominant condition has a 50% chance of being affected by that condition via inheritance of a dominant allele (e.g. Huntington’s disease) autosomal recessive disorder, on the other hand, requires two copies of the mutated gene (one from each parent) to cause the disorder x-linked recessive inheritance= a mode of inheritance in which a mutation is a gene on the X chromosome that causes the phenotype to be always expressed in males and in females who are homozygous for the gene mutation 6 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material genotype vs phenotype: genotype= is the genetic makeup of a cell in an organism phenotype= traits that can be observed in the organism, based on genes and environment selection can occur for specific phenotypes; a phenotype doesn’t always have to be visible- it can also be sensitivity to certain things, becoming depressed, tendency to be persistent, chance to develop a specific disease, etc. DNA (Deoxyribonucleic Acid) - the DNA is the recipe book for making proteins - its physical structure is described using the term double helix: a molecule of DNA is made from two linked strands that wind around each other and look like a twisted ladder; each strand has a sugar-phosphate backbone; one sugar-phosphate and a base created a nucleotide (the building block of RNA and DNA) - the DNA is a long chain of nucleotides that form base pairs: nucleotide A opposite T (A-T) nucleotide C opposite G (C-G) 7 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material 8 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Transcription and translation - in the nucleus a piece of DNA, a gene, is copied (=transcription) into messenger RNA (mRNA) - in the cytoplasm, the mRNA of the gene is translated into a protein at the ribosome (the ‘protein factory’) the genetic code- a gene contains information for making a protein - proteins are made of amino acids ( a protein can consist of one or more chains of amino acids = polypeptides) - there are approx. 20 different amino acids are used to make proteins - 3 nucleotides together (= triplet code/ codon) are the key to which amino acid will be produced in the protein step 1: transcription: from DNA to RNA - a gene from the DNA template is transcribed to a primary RNA - the difference between RNA and DNA: RNA has U instead of T nucleotide RNA is shorter than DNA RNA can leave the cell nucleus - only one copy of a recipe is allowed to leave the library! 9 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material step 2: splicing RNA into mRNA - exons and introns form a gene; however, only exons code for proteins; the primary transcript RNA reads the DNA, including the introns; however, the mRNA splices the exons together, removing the introns; the mRNA is then transported out of the nucleus into the cytoplasm where translation is going to occur step 3: translation of mRNA into a chain of amino acids - mRNA connects with a ribosome, and each mRNA condon merges/ sticks with transfer RNA (tRNA) anticodon - each tRNA molecule has an amino acid on one end and an anticodon on the other; appropriate condon combinations meet at the ribosome, determining the order of amino acids in the growing protein chain - each new amino acid combines with the previous one and starts to form a chain: the protein - when the mRNA is finished, the primary protein is completed; the mRNA may combine again with a ribosome to repeat the process (peptides vs amino acids- peptides are short chains of amino acids that have been linked by amide- or peptide-bonds) 10 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material step 4: post-translational protein processing - large proteins can be cut into smaller proteins, creating multiple proteins from one gene - transcription is precisely regulated (it requires an activated transcription factor to reach the nucleus) Evolution and genes - proteins’ ‘jobs’: o they are the building blocks of our body (muscle fibres are proteins) o can become part of the cell membrane to form receptors for neurotransmitters or hormones o are part of the cell structure and function (muscle contraction, connecting cells) o combines with other proteins and iron to transport oxygen (haemoglobin) in red blood cells o form ribosomes in order to create new proteins o products of the immune system to kill invaders o some function as hormones or even neurotransmitters o can serve as fuel for energy and heat production o can be an enzyme to metabolize chemical reactions (cellular glue or scissors) 11 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material enzyme example: - serotonin is a neurotransmitter; it is created from amino acid L-tryptophan; two enzymes (A and B) are needed to convert tryptophan to serotonin - enzyme C inactivated serotonin - serotonin is NOT a protein from your DNA, but the enzymes that make it are - DNA control of transcription can produce more or less enzymes - DNA via enzymes can control serotonin production Mutations - some DNA variations have no negative effects; others lead to disease (e.g., sickle cell disease) or increase one’s chances to disease (e.g., lung cancer) - single nucleotide polymorphism (SNP)= a SNIP is a one-letter place where the genome varies from another genome sequence; it can influence health, disease, drug response and other traits Crossing over (a form of mutation) - crossing over= the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during the development of egg and sperm cells (= meiosis) => new combination of alleles in the gametes (egg or sperm) is formed which translated into genomic variation in the offspring 12 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Other forms of DNA differences tandem repeat/ satellite DNA= a sequence of two or more DNA bases that is repeated many times in a chromosome; present usually in non-coding DNA; sometimes they help track inheritance in families and can be used for DNA fingerprinting in forensic studies translocations= occur when a chromosome breaks and the fragmented pieces re-attach to different chromosomes; the detection of the translocations helps diagnose certain genetic diseases and disorders; there are two types of translocation: balanced, in which equal parts of the two chromosomes are exchanged unbalanced, which involves unequal portions of chromosomes and leads to extra or missing genes duplication= a type of mutation in which one / more copies of a DNA segment is produced; it can cause genetic diseases like Charcot- Marie-Tooth (damage to the peripheral nerves=> muscle weakness) insertions and deletions= addition or loss of one or more nucleotides or sections of chromosomes; deletion is responsible for most cystic fibrosis cases and the cat cry syndrome 13 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Epigenetics - epigenetics is the study of heritable phenotype changes that do not involve alterations in the DNA sequence (phenotypical changes other than the DNA sequence in response to the environment – stress, food, smoking, radiation) e.g., ‘turning off’ of genes under certain circumstances - twin studies investigate differences in monozygotic (identical DNA and shared environment) and dizygotic (DNA same as regular siblings but with shared environment during gestation, birth and development) twins can share more light on heritable vs. environmental factors 14 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Cell communication and the endocrine system 15 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Neurons- structure and function - neurons consist of 3 parts: many dendrites (function: collect information- input- from other neurons) one cell body/ soma (function: integrates information) one axon (functions: sends information- output-throughout the body) - flow of information in neurons: input through dendrites integration through soma/ cell body output through axon - major types of neurons: sensory neurons interneurons motor neurons - major types of neurons: sensory neurons interneurons motor neurons sensory neurons (input cells- afferent-) - transmit neural information from sensory receptors to spinal cord and brain (bring information to the CNS) - have long dendrites and short axons - the dendrites and the cell body are outside CNS - the axon is inside CNS interneurons (association cells) - link sensory and motor neurons in CNS - branch extensively to better collect information from many sources - can be: star-shaped, with axon difficult to see amongst many dendrites pyramidal (pyramid shaped) with a long axon and 2 sets of dendrites (one at apex and one at the base) purkinje; neurons that transfer the information from the cerebellum to the rest of the brain and spinal cord - have short dendrites and short axons - the dendrites, cell body and axon are inside CNS (in the brain and spinal cord) motor neurons (output cells- efferent-) - send signals from the brain and spinal cord to muscles - have short dendrites and long axons - the dendrites and cell body are inside CNS (in the lower brainstem and spinal cord) - the axon is outside CNS 16 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Glial cells - glial cells aid neurons in processing information by providing: physical support and protection nutrients increase conduction (lit. glue neurons together) !!! glial cells do not transmit information themselves - types of glial cells: ependymal cells astrocytes microglia oligodendroglia Schwann cells 17 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Internal structure of a typical (nerve) cell - cell membrane- membrane surrounding the cell - nucleus- cell core, contains chromosomes and genes - nuclear membrane- surrounds the nucleus - endoplasmic reticulum- assembles proteins - Golgi bodies- wraps, addresses, and ships off proteins - microtubules- form the transportation network - microfilaments- reinforce the cell’s structure - mitochondria- supply energy to the cell - lysosomes- transport incoming supplies and remove and store wastes cell membrane - the cell membrane is lipid rich (it is fatty) - separates the intracellular and extracellular fluid - consists of 2 layers of phospholipid molecules: head: phosphate group= hydrophilic (binds with water) tail: fatty acid (lipid)= hydrophobic (does not bind with water) - only a few small (uncharged) molecules can passively traverse the phospholipid layers (e.g., oxygen, carbon dioxide) - basic receptor types on the cell membrane: ionotropic (ligand-gated ion channels)- ions are allowed to enter the cell membrane only when a neurotransmitter ‘docks’ on the sides of the gate metabotropic (G-protein coupled receptor)- when a neurotransmitter reaches the receptor, a G-protein is released 18 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material cytoskeleton - the cytoskeleton gives the cell shape and aids in the connection with other cell or cell transportation - it consists of: intermediate filaments microfilaments microtubules centrioles o protein filaments aid movement and support cell to cell connection - cells are connected in 3 ways: via desmosomes (flexible proteins; things can still pass between cells; e.g., skin tissue) via tight junctions (nothing can pass between cells; e.g., the lining of the gut is formed from tight junctions) via gap junctions (there’s space left for things to pass between cells; e.g., cardiac cells that contract together) 19 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material endoplasmic reticulum ER - the place where proteins are assembled - is made up of: rough ER smooth ER rough ER: part of the ER that has ribosomes attached to it; it plays a role in protein synthesis smooth ER: part of the ER with no ribosomes; is a calcium storage and it helps in the synthesis of fatty acids and steroids Golgi apparatus - creates vesicles to transport the proteins created in the ER and thus aiding the secretion of proteins or their use in the cell mitochondrion - generates the chemical energy needed to power a cell; the chemical energy that is produced in a mitochondria is stored in small molecules called ATP (adenosine triphosphate) - mitochondria have their own DNA, and it’s always inherited from the mother - ATP is the universal source of energy in the body; energy is released when a phosphate group (Pi) is separated from ATP (=>ADP) - ATP are energy-carrying molecules that capture the chemical energy obtained from the breakdown of food molecules and use it to fuel other cellular processes such as metabolic activity, transporting required substances across membranes and mechanical work, e.g. moving muscles; ATP is mobilised from storage and delivers energy to places within the cell where energy is required - when a phosphate group joins ADP, energy is stored 20 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Communication between cells Electrical communication - electricity is about the movement of electrons from a region of higher charge to a region of lower charge. The basis of the charge is the electron; the difference between the positive and negative charge is referred to as the potential (measured in volts) - the flow of electrons is referred to as a current; in the current, the electrons pass from the negative to the positive side. - the basis of electrical communication is the difference in ionic concentrations on either side of the neuron's cell membrane; positively charged ions are cations, negatively charged ions are anions - the movement of ions in and out of the cell is mediated by diffusion along a concentration gradient, as well as electrostatic pressure - diffusion is the process in which the moving molecules go from areas of high concentration to low concentration along a concentration gradient until there is an even distribution; due to the fact that ions are electrically charged, an electrical force exists between ions: like charges repel and opposite charges attract; cross the membrane, this force or electrostatic pressure is in action; however, the membrane is selectively permeable to various ions, most notably sodium (NA+) and potassium (K+) - electrical potential was in either a state of rest or a state of action: the resting potential and the action potential the resting potential - the difference in charge between intracellular and extracellular side is of approx. - 70mV and it’s called resting potential (potential energy) - ions critical to resting potential: cations: Na+ (sodium) and K+ (potassium) anions: Cl- (chloride) and A- (large protein molecules) - intracellular we have more A- and K+ and extracellular we have more Cl- and Na+ 21 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - the cell’s membrane channels, gates and pumps maintain the resting potential - the cell membrane is relatively impermeable to large proteins that are synthesized inside the cell (A- ); these large proteins’ negative charge is sufficient to produce a transmembrane charge (the resting potential) - to balance the negative charge in the intracellular fluid produced by the large protein aions (A- ), open channels allow potassium (K+ ) ions to cross the cell membrane; the potassium influx is limited by the concentration gradient across the cell membrane => there’s a slightly negative charge across the cell membrane = resting potential - however, sodium (Na+) can leak into the cell and may neutralise the resting potential (making the intracellular fluid less negative); to prevent this, we have sodium- potassium pumps - when a sodium ion leaks into the neuron, it is immediately escorted out by the sodium-potassium pump; 3 intracellular sodium ions (Na+) are always exchanged for 2 potassium ions (K+ ), this ensuring that the number of sodium ions is always larger in the extracellular fluid then inside, which in turn contributes to the negative resting potential. (=> outside is always slightly more positive then inside of the cell) the action potential - the action potential is a revers in an axon’s membrane’s polarity; it is a brief and large all-or-nothing potential that reverses the membrane’s polarity 22 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - it arises when the potential difference over the membrane exceeds a certain level- the firing threshold is at -50 mV - firing threshold (threshold potential)- at this threshold, the configuration of voltage-sensitive channels changes, and they open briefly to allow ions to pass through - action potential does not extinguish with distance and cannot be summed like gradual potentials => the neuron needs to wait (=refractory period) until the action potential is over before it can generate another action potential - at resting state, voltage-sensitive Na+ gates are closed (-70 mV); when the firing threshold of -50 mV is reached, the following happens at the membrane level: depolarization repolarization hyperpolarization resting potential depolarization: voltage sensitive sodium (Na+) gates briefly open => Na+ influx: difference between intracellular and extracellular space becomes positive (+30 mV) repolarization: voltage sensitive potassium (K+) gates open +> K+ efflux: difference increases to resting potential (-70 mV) hyperpolarization: potassium (K+) gates are still open, and the difference increases beyond resting potential (-73 mV) resting potential: K+ gates close and the difference decreases to -70 mV 23 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material postsynaptic potentials - during synaptic transmission, the presynaptic neuron (the neuron sending the message) releases a chemical called a neurotransmitter, which crosses the synapse - neurotransmitters interact with receptors of another neuron (the postsynaptic neuron); the neuron that receives the message transforms the message into an action potential, which travels down to the axon and releases a neurotransmitter into another synapse - receptors on the dendrites and soma receive incoming signals from other neurons: if the received message depolarizes the receptor, it produces an excitatory postsynaptic potential (EPSP)= cell B is ‘turned on’; an inhibitory input produces a hyperpolarisation called an inhibitory postsynaptic potential (IPSP)= cell B is ‘turned off’ Communication: synapse - there are many types of synapses: - synaptic transmission happens in 4 stages: synthesis and packaging release receptor action at postsynaptic membrane inactivation synthesis and packaging- can happen at the level of the cell body (DNA, mRNA) and the axon terminal (precursor chemical derived from food) release- action potential triggers a calcium influx that is released into the synaptic cleft (exocytosis) 24 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material receptor action at postsynaptic membrane- the transmitter crosses the synaptic cleft and 1 of the 3 can happen: depolarization (excitation) hyperpolarization (inhibition) modulation (inhibit or excite other chemical reactions) inactivation- the transmitter is deactivated in one of the following ways: diffusion away from the synaptic cleft degradation by enzymes reuptake in presynaptic cell uptake by glial cells (astrocytes) - there are two kinds of synaptic transmission: anterograde synaptic transmission= from presynaptic to postsynaptic neuron retrograde synaptic transmission- from postsynaptic to presynaptic neuron neurotransmitter release - the presynaptic membrane is rich in voltage sensitive calcium channels, and the surrounding extracellular fluid is rich in Ca2+ - the steps for neurotransmitter release: 1. when an action potential reaches the presynaptic terminal, voltage-senstive calcium channels open, allowing Ca2+ ions to flow into the cell 2. incoming calcium ions bind to calmodulin (=calcium-modulated protein), forming a complex 3. this complex binds to vesicles, which releases some vesicles (containing neurotransmitters) from filaments and induces others to bind to the presynaptic membrane 4. vesicles attached to the cell membrane empty their contents into the synaptic cleft by exocytosis (by first fusing to the cell membrane). long story short: when an action potential arrives at presynaptic terminal neurotransmitters packed in vesicles are released (=exocytosis) 25 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Communication: neurotransmitters - for a chemical to be a neurotransmitter, there are four ‘classical’ criteria: it has to be synthesized or present in the neuron when released, it must produce response in the target cell experimental placement (experimental manipulation) must result in same response a mechanism of removal must be in place classes of neurotransmitters amino-acids: with inhibitory effect: GABA with excitatory effect: glutamate monoamines (derived from amino acids): catecholamines (hormones made by the adrenal glands): dopamine (DA) noradrenaline (NA) adrenaline (a.k.a epinephrine) indolamine: serotonin soluble gases: nitric oxide carbon monoxide acetylcholine (Ach) - neurotransmitters have different effects depending on the receptors they bind with; each neurotransmitter has different receptors to bind with; the number of receptors varies, and it’s fully regulated=> the sensitivity to a particular neurotransmitter can increase or decrease 26 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Communication between cells: hormones - hormones aid the ‘long distance communication’ that takes place in the body - hormones are found primarily outside of the CNS (central nervous system) - hormones are released from the endocrine cells into the bloodstream and travel until they find their target cells (cells with a hormone receptor); organs like the heart and kidneys can also produce hormones - the endocrine glands are: pineal gland pituitary glands (anterior and posterior pituitary) thyroid adrenal glands: adrenal cortex and adrenal medulla pancreas gonads (testes/ ovaries) - there are 3 main chemical classes of hormones: monoamines (derived from single amino acids): thyroid hormones adrenaline noradrenaline dopamine peptides and proteins (most hormones are peptide hormones): LH (luteinising hormone) GH (growth hormone) vasopressin insulin oxytocin steroids (lipids; produced in the adrenal cortex and gonads; have as precursor cholesterol): cortisol estrogen testosterone 27 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material example of monoamines: catecholamines (hormones made by the adrenal glands) - hormones derived from the amino acid tyrosine - main types of catecholamines: dopamine adrenaline noradrenaline - play a role in stress response - different enzymes are involves in the process of transforming tyrosine in different hormones 28 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Adrenal gland - can be found on top of the kidneys - it is formed from: medulla adrenal cortex medulla- secretes amine hormones (adrenaline and noradrenaline) in response to sympathetic activation - dopamine is secreted by both the hypothalamus and the adrenal medulla Adrenal gland: cortex and medulla - different regions of the adrenal gland have cells specialised to produce different hormones: medulla produces adrenaline and noradrenaline 29 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material ! adrenaline and noradrenaline both can be considered neurotransmitters and hormones, depending upon their site of action. the cortex produces steroid hormones (including cortisol) The thyroid gland - the thyroid hormone pathway: hypothalamus released TRH (thyrotropin-releasing hormone) ↓ the pituitary gland releases TSH (thyroid-stimulating hormone) ↓ thyroid gland releases thyroid hormones T3 and T4 (also derived from tyrosine) - at the thyroid gland level, negative feedback can happen (hormones go up towards the brain instead of dispersing in the body) - iodine is necessary for the production of monoamines 30 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - the effects of the thyroid hormones: metabolic effect: low thyroid hormone (hypothyroidism) is related to slow metabolism and more weight gain cardiovascular: increase in blood flow and heartbeat, strengthens the effect of adrenaline body temperature: hyperthyroidism is related to sweat outbreaks and higher body temperature effects on mood, growth, and sexual functioning Proteins - they are a folded chain of amino acids - we obtain our amino acids mainly from food - protein hormones: insulin (regulated glucose uptake) growth hormone (regulated cell growth) gonadotropins (LH and FSH) - LH, FS and TSH are glycoprotein hormones (glycoprotein = protein with carbohydrates attached to it= ‘sugar coated’ proteins) - proteins have many functions; they can be: hormones (communicators) receptors (receive communication) enzymes (molecular glue/ scissors) Peptide hormones - their size varies from 3 amino acids to small protein - initially they are large proteins (preprohormones) found in ribosomes; these large proteins are ‘cut’ in the Golgi apparatus and stored in vesicles; when they are secreted, they are released together with other hormones - some peptides can be both neurotransmitters and hormones peptide hormones examples: ADH/ vasopressin: causes water retention in kidneys (anti-diuretic hormone) and vasoconstriction (vasopressin) oxytocin: causes milk release and uterus contraction during birth - both ADH and oxytocin are secreted by the pituitary gland - oxytocin and vasopressin are also involved in love and trust; oxytocin is involved in the process of bonding with our peers and helps us overcome avoidance of close proximity Steroid hormones - fat-like hormones, derived from cholesterol (which is a fatty acid) ! all steroids derive from cholesterol with the help of enzymes - are lipid- soluble - produced in the gonads and adrenal cortex - hormones of the gonads: testosterone estradiol 31 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material progesterone - main steroid hormone produced in the adrenal cortex: cortisol + DHEA, corticosterone, etc. Other hormones- hormones with local influence nitric oxide (NO) prostaglandins (omega 3/ omega 4) nitric oxide (NO) - a gas hormone - released with oxygen levels drop in certain areas of the body; it promotes vessel dilation, increased blood flow prostaglandins (omega 3/ omega 4) - derived from fatty acid - their production is inhibited by medication as Aspirin and Ibuprofen - play a role in immune response (cause inflammation, fever, pain) and childbirth (cause uterine wall contractions) - the condition of the endocrine glands can be described as hypo (too little) or hyper (too much) e.g: hypo/ hypersecretion: a substance is formed/ released in too small or too big quantities hypo/ hyper responsiveness or hypo/ hyper (in)sensitivity: the target cells respond or not to the hormones Neuroendocrine control - the CNS can control the endocrine glands: directly through an autonomic ganglion via hormones that reach a gland directly through hormones (released in the bloodstream) 32 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material The pituitary gland: the master gland - the pituitary gland is formed from: anterior lobe (frontside) posterior lobe (backside) - the pituitary gland is connected to the hypothalamus which has cells with ‘releasing hormones’ (secreted by neurons) that are transported to the pituitary gland - stimulant releasing hormones secreted by the hypothalamus: thyrotropin-releasing hormone (TRH) corticotropin-releasing hormone (CRH) gonadotropin-releasing hormone (GnRH) growth hormone-releasing hormone (GHRH) - inhibitors: somatostatin dopamine Posterior pituitary gland - produces hormones that are released directly into the bloodstream: ADH/ vasopressin: causes water retention in kidneys anti-diuretic hormone) and vasoconstriction (vasopressin) oxytocin: causes milk release and uterus contraction during birth 33 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Anterior pituitary gland - hypothalamic ‘releasing’ hormones are delivered to the anterior pituitary gland via the hypothalamic- pituitary portal system - once arrive, the releasing hormones bind to receptors on the pituitary cells to trigger the secretion of the pituitary hormones - pituitary hormones and their target organs: TSH > thyroid gland LH (luteinising hormone) / FSH (follicle-stimulating hormone) > ovaries and testes prolactin > milk glands GH > growth (many cells) ACTH (adrenocorticotropin) > adrenals side note: CRH- corticotrophin-releasing hormones DA- dopamine TSH- thyroid-stimulating hormone TRH- thyroid-releasing hormone GnRH- gonadotropin-releasing hormone 34 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material The immune system - the immune cells (cells that protect us against disease and illness) are also called leukocytes (=white blood cells) - when it comes to the body’s immune response we can differentiate between innate and adaptative immune responses - there’s also the possibility of the immune system to be hypersensitive - the main tasks of the immune system: counteract infections caused by pathogens (e.g., bacteria and viruses) keeps watch for mutated cells (e.g., tumours) causes inflammation repairs the damaged tissue disposed of damaged/ dead cells - the immune response involves: recognition of foreign material (that doesn’t belong to the body) as opposed to ‘self’ elimination of foreign material - 2 main types of immune response: non-specific: innate immune system (it is non-adaptive); innate immune response does not alter after repeated exposure specific: adaptive/ acquired immune response; adaptative immune response is highly specific for one particular pathogen and its response (usually) improves after each encounter - in a blood sample, we can find: red blood cells monocytes (a type of white blood cell that reside in your blood and tissues to find and destroy germs- viruses, bacteria, fungi, and protozoa- and eliminate infected cells) neutrophiles (type of white blood cell that act as your immune system's first line of defence) platelets (small, colourless cell fragments that form clots and stop or prevent bleeding) lymphocytes (they are the main type of cells found in lymph and play a major role in our immune response) 35 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - the cells of the immune system can be divided into two big categories: phagocytes (they eat the infected cells): granulocytes mono/ macrocytes dendritic cells lymphocytes (recognise and remove the threat): T-cells B-cells NK (natural killer) cells - the immune system fights against: infectious diseases caused by: bacteria (legionella, salmonella, chlamydia) viruses (HIV, COVID 19, influenza, common cold) protozoa (malaria, giardia) fungus (candidiasis, trichophyton - fungal nails) allergic reactions (eczema, hives, food allergies, asthma) autoimmune diseases (rheumatoid arthritis, Type I diabetes, MS, IBS) - immune system also defends us against ‘non-communicable diseases’ such as: cardiovascular disease cancer COPD (chronic obstructive pulmonary disease) diabetes - often, stress plays a major role in how well our body defends itself against infections and diseases and the other way around: the state of our help can and will impact the amount of stress we experience The process of viral infection - a viral infection can sometimes be quiet and become reactive (e.g., herpes simplex) and can become incorporated in our DNA 36 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - the process of a viral infection: a virus (=DNA/ RNA with a lipid coat) enters the cell replication: the DNA/ RNA of the virus is copied assembly: the cell created many viruses that gather inside the said cell release: a cell releases (sometime by bursting= the cell is destroyed) the virus that is ready to invade other cells Innate immune response - the innate immune response is the first line of defence - it is formed by our external and chemical barriers: the skin, mucous membrane, secretions (pH, lysozymes= antimicrobial enzyme) Complement (innate protein defence) - central part of the innate immunity that serves as a first line of defence against foreign and altered host cells; it consists of a special set of proteins that are activated by infection; they coat and mark the invader NK-cells (Natural Killer cells) - a type of lymphocyte cell and part of the innate immune system - recognizes tumour cells and virus infected cell in one of the two ways: via components exposed on the surface of the cells the absence of these components that normally would be there (= the cell is too smooth on the surface to be a healthy, ‘friendly’ cell) - causes infected cells to die - apoptosis= self-destructions of cells from inside; NK cells induce apoptotic cell death in their targets 37 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material The eating cells (phagocytes) - granulocytes- present in large numbers; they eat the threat and then die; pus is an accumulation of dead granulocytes - macrophages (‘big eaters’)- slower cells that are larger and live longer; they are activated forms of monocyte; after they ate a threat they present part of ‘what they ate’ on the outside of the cell - dendritic cells (‘spikey ones)- can be found in tissues near the external environment (e.g., skin); they take up a large surface area and present antigens on the outside of the cell (like macrophages) Inflammation (=innate inflammatory response) - inflammation is a ‘call to action’ for the cells of the innate immune system to come to a site and help the fight against threat; it is the response of body tissues to harmful stimuli (pathogens, damaged cells or irritants) - the process: o white blood cells (leukocytes) release chemicals to stimulate inflammation; it causes redness, swelling, het, itch and pain o mast cells (a granulocyte) release histamine and cytokines o local blood capillaries become ‘leaky’ and therefore cause redness, swealing, heat, itch, pain o the complement system is activated, and blood clotting starts to happen o neutrophils and macrophages are called to the site where the threat is o more cytokines are released (messenger molecules) o the brain is signalled and we feel sickness (lethargy, muscle pain, nausea) in order to stop our activity and rest o cytokines cause increase in body temperature: fever mast cells- granulocyte which plays a central role in allergies; it released histamine and chemokines histamine- substance that causes inflammation chemokines- attract other cells of the immune system to site 38 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Antigen presenting cells - these cells are macrophages or dendritic cells who have digested and presented particles of the invading pathogen - this forms the basis of activating the adaptive immune response long story short & keywords: innate/ non-specific immune response: - 1st line barriers: skin, mucus, pH, enzymes o complement o histamine o KN cells o phagocytotic cells (granulocytes, macrophages, dendritic cells) o inflammation o APC’s (antigen presenting cells) 39 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material The adaptative (acquired) immune response - MHC plays a vital part in the process of recognising the self vs the non-self; MHC= major histocompatibility complex - MHC can be found on the outside of all cells and displays both ‘self’ component (indicates that a cell belongs to the body) but also virus, bacteria, or cancer component - the MHC on antigen-presenting cells (macrophages and dendritic cells) is the starting point for adaptative immune response MHC presentation of self and non-self-antigens - foreign proteins and self-proteins withing the cytosol (liquid that surrenders the intracellular organelles) are broken down into fragments that are antigens - the foreign antigens combine with MHC class I molecules and stimulate cell destruction - self-antigens combines with MHC class I molecules do not stimulate cell destruction (if everything goes well) Antigens - antigen= all substances that can be recognized by the adaptive immune system - molecules capable of stimulating an immune response (= the creation of antibodies) - antigens can be detected and recognised either by the B-cells or T-cells: B-cells recognise the pathogen directly T-cells recognise what is left of the pathogens when presented on a MHC B lymphocytes (B-cells) - B stands for bone-marrow - B-cells origin and mature in the bone-marrow - they recognise antigen that is not bound to a MHC protein (e.g., an intact bacteria) - one B-cell can recognise only one specific antigen - B-cells display and release antibodies 40 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Antibodies (=immunoglobulins) - recognise and bind the antigen - look like a letter Y - each antibody has a: o specific part which binds to antigen o neutral part binding to B-cell, immune phagocytic cells, etc - bacterial cell (antigen) bonds with antibody - circulating antibodies inhibit infection by: o preventing the antigen from binding to its target (neutralization) o tagging a pathogen and destroying it with the help of macrophages or neutrophils (opsonization) o activating the complement cascade- complement ‘hugs’ the pathogen in pores (complement activation) B-cell activation - B-cell activation process: a B-cell binds and digests an antigen the cell presents the antigen on MHC a helper T cell recognises the MHC => the B-cell is activated and antigen complex has been formed B-cell multiplies into: plasma cells (secreting other identical antibodies= ‘monoclonal’ antibodies) memory B-cells (long term memory => the body can remember that it encountered the same pathogen in the past) 41 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - when exposed to a pathogen for the first time, the plasma cell secretes antibodies; when re-exposed to the same pathogen, the memory cells differentiate into plasma cells with greater among of antibodies for a longer period of time 42 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material T-lymphocytes (T-cells) - originate from the bone-marrow stem cells but then mature in the thymus (T stands for thymus) - T-cells recognise antigens only when they are bound to the major histocompatibility complex (MHC) - T-cells are highly specific: we have 10 million different one, each able to recognise one specific antigen (=> sometime it might take days for the right T-cell to come forth and deal with the pathogen the body has to fight against) - cytotoxic T-cell (Tc)- a type of T-cell that recognises antigens when bound to infected cells (cancer, virus, transplanted cells = cells that might hide the threat inside) and then destroys these cells; it is part of the cell-mediated immune response T-helper activation - a t-helper (Th) cell can become activated and it helps either a B-cell or a cytotoxic T-cell (Tc) 43 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - in this context we can distinguish 2 responses: humoral immune responses cell-mediated immune response o humoral immune response (= it is about what happens in the body fluids) Th2- a T-helper cell interacts with a B-cell, releases cytokines and helps the B-cell divide, differentiate and produce antibodies o cell-mediated immune response (= it is about what is in the cell) Th1- a T-helper cell that with the help of phagocytes released cytokines and helps cytotoxic T-cells destroy intracellular pathogens - to sum up: a helper T-cell becomes activated, causing it to release cytokines; this activates the humoral (B-cells) or the cell-mediated (cytotoxic T-cells) immune response long story short: 44 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Vaccines - the primary method of controlling viral disease is by vaccination (intended to prevent outbreaks by building immunity to a virus or virus family) - a vaccine may be prepared using: weakened live viruses killed viruses molecular subunits of the virus - live viruses lead to better immunity, but have the possibility of causing disease at some low frequency; killed viral vaccine and the subunit viruses are both incapable of causing disease, but in general lead to less effective or long-lasting immunity - live vaccines are usually made by attenuation (weakening) of the “wild-type” (disease-causing) virus by growing it in the laboratory in tissues or at temperatures different from what the virus is accustomed to in the host; the adaptation to these new cells or temperature induces mutations in the virus’ genomes, allowing them to grow better in the laboratory while inhibiting their ability to cause disease when reintroduced into the conditions found in the host; they still cause an infection, but they do not grow very well, allowing the immune response to develop in time to prevent major disease - the danger of using live vaccines, which are usually more effective than killed vaccines, is the low but significant risk that these viruses will revert back to their disease-causing form by back mutations - some vaccines are in continuous development because certain viruses, such as influenza and HIV, have a high mutation rate compared to other viruses or host cells; with influenza, mutation in genes for the surface molecules helps the virus evade the protective immunity that may have been obtained in a previous influenza season, making it necessary for individuals to get vaccinated every year When the immune system goes wrong… = > immunodeficiency= failure/ insufficiency or delay in the response of the immune system o e.g., HIV virus infects the T-cells and when left untreated it causes has severe consequences for regular immune functioning; CD4+ cell count is a measure for HIV activity = > allergy (hypersensitivity) = > autoimmunity Allergy - when first exposed to an allergen, antibodies are synthesized by B-cells in response to a harmless antigen (e.g., pollen); these antibodies (IgE) bind to mast cells - at the second exposure mast cells release histamines and other modulator causing symptoms of allergy = > allergic reaction 45 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - anaphylactic shock: an extreme allergic response that causes dilation of (local or systemic) blood vessels, and fluid loss => immediate loss of blood pressure, breathing difficulties, nausea; this can be life threatening and usually happens very fast o in case of an anaphylactic shock, injections with adrenaline administered in the thigh muscle can save someone’s life (EpiPen) Autoimmunity - autoimmunity is a type of hypersensitivity to self-antigens that affects approximately five percent of the population - most types of autoimmunity involve the humoral immune response (antibodies are produces as a response to a self-antigen) - an antibody that inappropriately marks self-components (=body components) as foreign is termed an autoantibody e.g., Lupus is an autoimmunity to DNA and/ or proteins, which led to varied dysfunctions of the organs Stress and sickness - high levels of psychological stress are related to increased percentage of developing cold; stress can influence the level at which outside threats impact our health 46 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Homeostasis - homeostasis- a self-regulating process by which a living organism can maintain internal stability while adjusting to changing external conditions; homeostasis is the process that: regulates body temperature regulates glucose levels in the blood regulates oxygen in the blood regulates blood pressure regulates lipid levels in the blood ‘collaborates’ with the neurotransmitters, hormones, immune system regulates and balances bodily processes requires detection, action and feedback systems Eating - reasons we eat: helps maintain homeostasis it’s a pleasant activity it has a social aspect keeps us warm helps us build our body to stock energy to gain muscle power to be able to think (use the brain) to have energy available for the metabolic processes Digestion in the gastrointestinal (GI) tract 1. the mouth grinds the food and the saliva contains enzymes that facilitate the breakdown; it also provide the lubrication needed to be able to swallow the food 2. the food is transported via oesophagus and the carbohydrates are digested and transformed into simple sugars 3. in the stomach bacteria are killed by the low pH environment (=acidic); the food is broken down and the digestion starts; the proteins are broken down into amino acids 4. fats are broken down (or emulsified) by bile (which is made by the liver and stored in the gallbladder) which is released into the duodenum; 5. small intestine absorption 6. large intestine absorption 7. rectum (for fluid absorption) 8. anus (for waste elimination) 47 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Absorptive/ gastric state - the absorptive or gastric state is the phase when nutrients are being absorbed into the bloodstream; occurs after a meal when your body is digesting the food and absorbing the nutrients (catabolism exceeds anabolism) - nutrients are broken down, absorbed from the GI tract into the blood and then distributed and metabolized for use and storage Biomolecules - the most relevant biomolecules in our bodies: proteins (/peptides) fats (lipids) carbohydrates - these biomolecules are transformed during digestions into: amino acids (from proteins) triglycerides (from fats/ lipids) glucose (from carbs) proteins: an amino acid is the unit of a protein or peptide (peptides are smaller than proteins) carbohydrates (sugar, starch, and fibres): catabolism= the breakdown of complex molecules to release energy (e.g., disaccharide breakdown of sucrose result in table sugar) anabolism= generating complex molecules from simple ones to stare its energy (e.g., glycogen-a polysaccharide- refers to the storage of carbs in animals- it is composed of glucose subunits that can be ‘cut’ when and used when the body needs energy) lipids: when lipids are catabolised we obtain glycerol and fatty acids (long chains) when lipids are anabolised we obtain triglycerides (=body fat) and phospholipids (used for the cell membrane) 48 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material - from lipids we can also obtain steroids; cholesterol promotes cell membrane fluidity (making the cell flexible) and if synthetized (metabolized) it produces hormones such as estrogen transport of fatty acids in the blood: fatty acids are lipid thus water insoluble; they are transported in the body with the help of lipoproteins (=transport units produced by the liver for the lipids to be transported throughout the body); lipoproteins are a combination of protein, triglycerides, and cholesterol in the phospholipid membrane - there are two types of lipoproteins: LDL- low density lipoprotein (bad ‘cholesterol’); it contains more cholesterol and less proteins HDL- high density lipoprotein (good ‘cholesterol’); it contains less cholesterol and more proteins absorbative state: glucose - glucose results from the metabolization of carbohydrates - glucose is: used for energy (used by all cells) stored as glycogen (in muscles and liver) transformed into far (lived and fat cells) 49 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material absorbative state: lipids - fatty acids are taken up by the adipose (fat) tissue and combined with a α- glycerol phosphate form triglycerides (=lipogenesis); for the synthesis of triglycerides, we also need glucose absorbative state: amino acids - amino acids are anabolized into new proteins (to be used by the muscles, for example) - they are metabolised in α- ketoacids for energy and into fatty acids for storage - daily our diet consists of 50-75% carbs but the body is composed only in proportion of 1% of carbs; in general, women have more fat on their bodies as opposed to men Postabsorptive state, fasting phase and intestinal phase - the postabsorptive phase begins approx. 4 hrs after the food was eaten (after 4 hrs of fasting) - in order to maintain a stable blood glucose supply, the stored nutrients are mobilized and used - 2 main actions take place: glycogenolyses= glucose is released from glycogen glucogenesis= new glucose is being made from amino-acids (α- ketoacids) and fatty acids (glycerol) ! -lysis= something is broken down; -(neo)genesis= something is being formed/ produced - triglycerides are converted into ketones for fuel energy: cell respiration: ATP ATP= the metabolic process of converting biomolecules into energy; it required oxygen and water; it result in ATP, CO2 and heat - to increase the efficiency of mitochondria and therefor the energy it produces high intensity exercise is recommended Control of the absorptive and postabsorptive states - insulin and glucagon are the hormones that: control the uptake and the breakdown of the protein, glycogen and triglycerides control the cells to use glucose during the absorptive phase and fat during the postabsorptive phase stimulate glucose uptake by the liver during the absorptive phase and gluconeogenesis and glucose release during the postabsorptive phase 50 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Glucose in blood - glucose levels fluctuate during the day; stress can raise glucose levels at dangerous levels - a healthy person’s glucose levels range between 3,5-8 mmol/l insulin= a polypeptide hormone produces and secreted in the pancreas; the pancreas monitors the glucose levels in the blood and when these are high it secretes insulin; when the insulin levels are low, the pancreas stops producing insulin - insulin stimulates: the uptake of glucose by cells conversion of glucose to glycogen and fat conversion of amino acids to proteins storage of glycogen, fat, and proteins - insulin-sensitive cells respond to insulin binding by increasing the rate of glucose entry - when glucose levels are low the pancreatic cells secrete a peptide hormone called glucagon glucagon= hormone which stimulates conversion of glycogen into glucose; promotes release of fatty acids and stimulates conversion their conversion into ketones (=lipolysis); it stimulates gluconeogenesis - glucose levels raise and fall during and after each meal; starch-rich foods cause this spike and fall in glucose to happen less drastically (so we don’t experience the ‘sugar-dip) - abnormally low glucose levels (=hypoglycemia) are detected by chemosensory neurons in the CNS, which responds by activating the sympathetic nervous system; adrenaline acts to increase the release of glucose and new assembly of glucose 51 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie234 | [email protected] Want to earn $1.236 Distribution of this document is illegal extra per year?  Stuvia.com - The Marketplace to Buy and Sell your Study Material Hunger - factors influencing hunger: high glucose and insulin= less hunger appealing food= more hunger stress= can increase or decrease appetite high body temperature= less hunger etc… Thirst - we have two fluid-filled compartments in the body: intracellular fluid (in the cytoplasm) extracellular fluid, which includes: intravascular fluid (blood plasma) interstitial fluid (between the cells) cerebrospinal fluid (CSF) - there is movement between the fluid compartments that allows cells to survive; the extracellular fluid acts in a supporting role to the cells and is controlled by brain mechanisms that monitor its levels; the brain does this by promoting thirst as the motivator for drinking - there are two types of thirst: osmotic thirst- occurs when the solute concentration of extracellular fluid increases (it becomes saltier) and takes water from the intracellular fluid (which may place the cells in danger of damage); osmoreceptors (located in the anterior hypothalamus and other areas) detect changes in the concentration of the interstitial fluid (fluid between cells) 52 - Laura C./ Tilburg University/ 23-24/ Biological Psychology Downloaded by: alexie2