lecture 26 Flashcards
2 different levels of consciousness
- Perceptual (primary): awareness of one’s own sensory perceptions
- Reflective: awareness of being aware of one’s thoughts; attributing mental states to others
Medicine
practice that deals with conflicts, whose main function is to intervene on the side of one of the contenders-the patient
Darwinian Medicine
the hunt for evolutionary explanations of why were are susceptible to disease or discomforts
Categories of evolutionary explanations for disease
novel environments, design compromises, evolutionary legacies, defenses, infection, genes
Novel environments examples
professor that went back in time and was the only one wearing glasses because others didn’t have sight issues associated with close up tasks (reading); human body has only recently adapted to its current environment with lots of high-fat foods; the leading causes of death are now heart disease, cancer, stroke which are different that previous prominent causes of death, these things are killing us because our evolution has not kept up with the rapidly changing environment
Design compromises
we have certain trade offs associated with over-designing any one body system that in turn disrupts the functionality of the organism as a whole
Evolutionary legacies
ancestral design has stuck around even if it doesn’t optimize functioning; ex. we still use the same tube for eating and breathing even though it can lead to choking, the retina is actually strapped on backwards which causes us to have a blind spot
Defenses
Avoidance and repair- when we get injured, the injured region has increased sensitivity which leads us to avoid touching it and allows it to heal better; symptoms such as cough or fever can help get over an infection
Smoke-detector principle
having a severe response to something that actually doesn’t pose a real threat is only a minor inconvenience (allergies), but there are far worse consequences for failing to mount a response if there is a real threat- could result in death
Infection: evolutionary arms race
Red queen hypothesis; human beings are in constant battle with infectious organisms that are constantly being fine-tuned by evolution
Pathogen manipulation
the pathogen manipulates the host’s physiology or behavior to facilitate its spread
Adaptive host response
the host responds to infection in a manner that is beneficial to the host, usually to the detriment of the pathogen
Example of pathogen manipulation: Shigella enteritis
causes symptoms that include diarrhea and vomiting which allows it to maximize its spread because it spreads to others through toilets/sewers
Vector-borne vs. directly transmitted disease
vector-borne diseases are much more likely to bring death to the host; graph shows that infections that have more waterborne outbreaks cause more deaths
toxoplasma gondii: example of altered host behavior
infects mice which are just their intermediate host and changes the behavior of the mice to make them less afraid of predators and more likely to venture out into the open; this behavior change increases the chance that infected mice will be consumed by the parasite’s final host, cats; correlation between uncertainty avoidance (less fearful) and higher infection rate; also correlation between masculine sex roles and prevalence of T. gondii-parasite may be making males more masculine to increase mating and spread of disease
Rabies virus and host behavior
Rabies infection results in brain inflammation which changes behavior of host, making host more likely to bite another individual and spread the disease to another victim
Malaria infection
malaria increases attractiveness of humans to mosquitos, making them more likely to bite and suck the blood of the infected and then facilitating the spread to the others who are bitten by the same mosquito
Fever in locusts
locusts that had infection spent more of their time basking in the sun in order to give themselves a fever to better fight the disease
Behavioral fever in the desert iguana
they regulate body temp by moving to warmer or cooler locations; iguanas that were injected with dead bacteria chose higher body temps and spent more time in the warmth; another study infected lizards with live bacteria and then manipulated the temperature they were housed at; lizards kept at lower temperatures mostly died while those kept at high temps had high survival rate; suggests fever is adaptive for the iguanas
Syphilis and malaria study
syphilis patients that were intentionally infected with malaria showed an increased probability of recovery from syphilis
Study: fever and the common cold
adults were intentionally infected with rhinovirus 2 (common cold) and then were treated with over the counter meds; placebo group who didn’t take drugs suffered less stuffiness and made more antibodies to the virus, reducing the fever lowered the body’s ability to fight disease
Huntington’s disease
transmitted by an autosomal dominant gene; produces a mutant form of the protein htt, which aggregates in brain causing neurodegeneration; mutation caused by string of trinucleotide repeats; phenotype isn’t normally displayed until late in reproductive window, making it transparent to natural selection
The Health Benefit Hypothesis of H.D.
- Fitness benefit: HD+ individuals have higher fertility levels and will have more offspring
- Survival benefit: mutant HD allele confers health benefits (lowered incidence of cancer) during asymptomatic periods
p53 and htt
htt protein produced by those with H.D. causes upregulation of p53, which is an immune protein involved with destroying damaged cells and vital for prevention of unchecked cellular replication in cancer; better health in HD patients may be associated with more p53 which upregulates immune system
