bio dec3 Flashcards
why can the spleen be considered a large lymph node?
because it contains white pulp filled with B and T lymphocytes that are responsible for humoral and cell-mediated immunity.
Hardy-Weinberg equation
p2+2pq+q2=1 and q+p=1; q=frequency of recessive allele,
p=frequency of dominant allele.
to find heterozygote allele type: 2pq
erythropoietin
hormone that increases red blood cell mass at high altitude (low O2). body’s compensation for low O2 loss
where is unconscious movement coordinated
the cerebellum
disruptive selection
shifting in allele frequencies of population to either extreme.
when do sperm start to be produced
at puberty
gametes possible
2^n where n is the number of heterozygous pairs
cells of the stomach
parietal cells - produce HCl. chief cells - produce pepsinogen that’s activated to pepsin by HCl. pepsin digests proteins. G cells - make gastrin, hormone that stimulate acid secretion in parietal cells mucosal cells - make mucus that lines stomach.
absorption in small intestine
bile helps out, villi and microvilli provide increased surface area for absorption . all nutrients go to the liver first and then go into blood circulation. SI absorbs amino acids, hydrolyzed fats, water, monosaccharides, and vitamins.
how are fats absorbed by the body
absorbed by lymphatic system. transport fats to thoracic duct.
lymphatic system
collect excess interstitial fluid (lymph) and carry it back to the circulatory system.
How is lymph moved
mainly by the pressure of skeletal muscles - act against lymph vessels, and move the liquid forward. The liquid inside the lymph vessel is at a very low pressure and because of the pressure difference, liquids from the tissues are drawn into the lymph system. returned to the blood via lymph vessels that drain into the large veins of the cardiovascular system.
lacteals
collect fats from small intestine and transport them to the circulatory system.
where does lymphatic system join circulatory system
at the thoracic duct.
lymph nodes
contain leukocytes which help filter the lymph and remove foreign particles. cleanses/filters extracellular fluids.
respiratory system progression
nose/mouth, pharynx, larynx, trachea, lungs, bronchus, bronchiole, alveolar ducts, alveolar sacs, alveoli
surfactant on alveolus
reduces surface tension along alveoli and facilitates gas diffusion across membrane. also prevents alveolar collapse
partial pressure of gases in alveoli
- greater in the alveoli than in the blood so the net diffusion of oxygen is from alveoli to capillaries where RBCs can become oxygenated.
- partial pressure of CO2 is greater in the blood than in the alveoli and the net diffusion of CO2 is from the capillaries to the alveoli → then can be eliminated from the lungs through exhalation.
functions of the nose and mucus
detect odors, warm and humidify inhaled air, filter particulate matter.
nasal passage, bronchioles, and resp. passageway is lined with mucus that keeps passages moist and traps any particulate matter. cilia of epithelial cells move mucus towards pharynx for expulsion via coughing or swallowing.
membranes around lung
surrounded by visceral (adjacent to lung) and parietal (outer) pleura with interpleural space in between. pressure differential between interpleural space and lungs keeps lungs inflated.
inhalation and exhalation - movement of muscles
inhalation: diaphragm contracts, external intercostal muscles contract moving rib cage up and out. air enters lungs as a result of the vacuum that is created in them.
exhalation: diaphragm relaxes, external intercostal muscles relax, chest cavity size decreases.
respiratory centers
cluster of neurons in medulla oblongata that regulate ventilation. their rhythmic discharges stimulate contractions in the diaphragm and the intercostal muscles.
chemoreceptors
can modify neural signals for respiration. some found in aorta (aortic bodies) and carotid artery (carotid bodies) that connect to the medulla. carotid bodies respond to changes in pH and partial pressure of CO2 in blood. When a drop in pH is detected, rate and depth of ventillation are increased.
change in pH of blood with CO2,
as CO2 in blood increases, pH drops because CO2 reacts with water to form carbonic acid which lowers pH.
where does transcription and translation happen?
transcription happens in nucleus and product leaves through nuclear pores
translation happens in cytoplasm
possible mutations in DNA
base substitutions: one base pair substituted for another transition - substitution of purimidine for another pyrimidine or purine for another purine.
transversion: subs. of a pyrimidine by a purine or vice versa
deletions: one or more nucleotides are lost from a sequence insertions: one or more nucleotides added to a sequence. may also be inserted at an incorrect location
repairs in DNA
direct: reverses damage without cutting phosphate backbone - ex. removing methyl group to restore original base.
base excision repair: when incorrect bases are in DNA. damaged base is recognized by glycosylase and hydrolytically removed from phosphate backbone. correct base is inserted and sealed by ligase. mismatch repair: fixes incorrect pairings
nucleotide excision repair: removes thymine dimers and bulky adducts. area of DNA surrounding and including damaged portion is unwound and endonuclease makes cuts on both 5’ and 3’ sides of the damage. base are removed by an exonuclease and DNA resynthesized using sister strand as template. ligase seals it up.
post-replication repair: used to repair double strand breaks. recombinational repair where single strand of DNA from a homologous chromosome is used to resynthesize the missing portion. broken ends can be rejoined directly and ligated together. original sequence is not always maintained and mutations such as translocations can often occur as a result.
thymine dimers
caused by UV radiation. nucleotide excision repair mechanism removes them.
Holliday model for recombination
explanation of events that occur during recombination. homologous pairs line up endonuclease nicks a single strand on each homolog at the same place. homologs exchange strands and are ligated together forming the Holliday structure. branch migration can occur, incorporation a portion of the opposite strand into each
molecule cleavage occurs: if same strands are cleaved, original chromosomes are reformed, if opposite strands are cleaved, recombinant chromosomes formed.
numerical abnormalities
aneuploidy - one or more chromosomes are missing or are present in more than the normal number. usually from nondisjunction.
euploidy - extra complete set of chromosomes are present or missing.
mixoploidy - mosaicism - 2+ genetically different cell lines within a single individual derived from a single zygote.
chimerism - 2+ genetically different cell lines within a single individual derived from different zygotes.
structural abnormalities
occur when part of chromo is duplicated, deleted, or switched to another part of the chromosome. chromosomal number is normal, but there is an excess or deficiency in genetic material can happen from recombination malfunction or misrepair of chromosome breaks.
autosomal monosomy
always lethal.
mitochondrial DNA
double stranded and short portion of triple stranded, circular DNA. has 37 genes - 24 code for RNA, 13 code for polypeptides which are used in the respiratory complexes that produce ATP.
cystic fibrosis
cause by loss of function mutations in CFTR gene. effects gene that codes for membrane protein that transports chloride ions in and out of cells. if chloride can’t leave cell, water doesn’t flow out of the cell and disrupts the normal balance of salt and water and results in the buildup of airway secretions.
huntington disease
from gain of function mutation that produces autosomal dominant disorder characterized by neurodegeneration. also results in uncontrollable mvmts, personality alterations and memory loss.
caused by expansion of triplet repeat - causes more glutamines to be inserted in the protein product and changes its function. results in cell death.
proto-oncogenes
non mutant versions of genes that control cell proliferation. a mutation that results in gain of function can alter a gene to an oncogene and cause hyperproliferation which can result in cancer. can be activated by: amplification (lots of extra copies of gene present), point mutation (leading to excessive cellular response), chromosomal translocations (novel gene created), transposition (gene moved from a relatively inactive area of chromatin to active area)
tumor suppressor genes
inhibit pathways that lead to cancer. mutation in tumor suppressor gene causes loss of function of product which can result in cancer. both copies of allele must lose function for cell to be affected. loss of function in a tumor sup. gene can occur through: deletion of portion of chromo with gene, point mutation w/in DNA sequence of gene, methylation of DNA that prevents gene from being transcribed.
gene therapy
to correct genetic mutations. affected gene can be identified and malfunction can be corrected through molecular manipulation. approaches:
- inserting a normal gene into genome to replace bad gene - most common
- replacing bad gene through homologous recombination
- repairing mutant gene by reversing original mutation
- altering regulation of a gene
nephron
functional unit of the kidney about 1 million in kidney
structure of kidney
cortex - outermost layer of the kidney (like the brain)
medulla - sits beneath cortex.
renal hilum - deep slit in center of medial surface. renal artery, vein, and ureter enter and exit through here.
renal pelvis - widest part of ureter, spans almost entire width of renal hilum. has portal system - 2 sets of capillaries in series that blood travels through before going back to heart.
2 sets of arterioles: afferent - lead to capillaries called glomeruli. efferent - branch out from them. Leads to vasa recta capillaries. (“A before E with C in between).
Bowman’s Capsule: cup like structure surrounding capillaries in the kidney. leads to a long tubule with: proximal convoluted tubule, descending and ascending limbs of the loop of Henle, distal convoluted tubule, and collecting duct.
Bowman’s capsule
cup like structure surrounding capillaries in the kidney. leads to a long tubule with: proximal convoluted tubule, descending and ascending limbs of the loop of Henle, distal convoluted tubule, and collecting duct.
kidney filtration
- some blood is filtered into the Bowman’s space - called filtrate.
- molecules or cells that are larger than glomerular pores will remain in the blood.
- first blood passes through glomerulus and into bowman’s capsule, then to efferent arterioles and through vasa recta.
filtrate
similar to blood, but doesn’t contain cells or proteins. filter can select based on size. anything that makes it to the filtrate and is not reabsorbed will be lost from the body. isotonic to blood so neither capsule or capillaries swell.
kidney secretion
- nephrons can secrete salts, acids, bases, and urea into the tubule with active and passive transport.
- kidneys get rid of ions or other substances that are in excess. excretes wastes that are too large to pass through glomerulus pores some filtered out compounds may be reabsorbed - ex. glucose, amino acids.
nephron function
- use osmolarity gradients and selective permeability to reabsorb things from the filtrate and selective excrete wastes.
- uses selective permeability in the different parts of the nephron.
- descending limb of loop of henle is permeable to water but not salt, ascending limb opposite.
- collecting duct almost always reabsorbs water but amount varies. hormones can alter permeability
- kidney can alter osmolarity of interstitium tissue around tubule. changes ability to absorb and excrete compounds.
- combo of osmolarity gradient and selective perm = countercurrent multiplier system
flow of filtrate
proximal convoluted tubule: glucose, amino acids, vitamins, majority of salts reabsorbed with water
descending loop of Henle: only permeable to water. concentration of surrounding tissues increases going down and drives water out of tubule.
ascending loop of Henle: permeable only to salt. filtrate moves up towards cortex, concentration in area drops and salt actively pumped out.
distal convoluted tubule: maintains same conc. as cortex by reabsorbing water and salt. final concentration depends on permeability of collecting duct. - influenced by ADH and aldosterone.
aldosterone
steroid hormone - secreted by adrenal cortex in response to decreased blood volume. also released by adrenal glands in response to increase in angiotensin.
alters ability of the collecting duct to reabsorb Na. increases blood volume and pressure.
ADH
antidiuretic hormone/vasopressin - peptide hormone.
changes permeability of collecting duct - allows more water to be reabsorbed by making cell junctions of duct leaky.
increased concentration of interstitium will cause reuptake of water from tubule.
made in hypothalamus, stored in posterior pituitary, secreted when blood osmolarity is high.
inhibited by alcohol and caffeine
kidney excretion
anything that doesn’t leave tubule is excreted. collecting duct = point of no return.
filtrate collects in renal pelvis after tubule. fluid is mostly urea, uric acid, and excess ions. fluid moves through ureter to bladder where it is stored. urine excreted through urethra.
shouldn’t have blood, protein, or glucose in healthy urine.
hepato-
prefix for things related to liver (think hepatitis=inflammation of the liver)
