EXTRA BIO 2
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contain G cells that secrete gastrin, whcih induces parietal cells to secrete more HCl and signals the stomact to contract and mix its content
What does the presence of chyme cause?
causes brush border enzymes to secrete disaccharidases
duodenum secretes enteropeptidase, whcih activtes trypsin
peptide hormone that causes pancreatic enzymes to be released into the duodenum
regulates the pH of the digestive tract by reducing HCl secretion
it is an enterogastrone (hormone that slows motility through the digestive tract)
stimulates secretion of bile
Where else beside the mouth are fats digested?
small intestine with pancreatic lipase
major pigment of bile
travels to the liver, where it is conjugated and secreted into the bile for excretion
Process of amino acids and carbos through small intestine.
secondary active transport and facilitated diffusion into the epithelial cells lining the small intestine; they then move across the epithelial cells into the intestinal capillaries; a concentrationg radient then lalows simple carbs and amino acids to diffuse into capillaries
an outpocketing that accepts fluid exiting hte small intestine through the ileocecal valve and is the site of the appendix
cuplike structure surrounding the nephron
relaxation of the urethral sphincter in response to increased pressure in the bladder
Where is hydrostatic pressure higher, glomerululs or Bowman's capsule?
What does the liver do to ammonia?
converts it to urea
reuptake for use in the bod
Explain a tip for the kidney structure.
segments that are horizontal are focused ont eh the identity of teh particles (keep what is needed; lose what is not)
vertical: focused on volume adn concentratoin
proximal convoluted tubule
amino acids, glucose, water-soluble, vitamins,and salts are reabsorbed along with water
site of secretion for a number of waste products, including hydrogen ions, potassium, ammonia, and urea
descending limb of the loop of Henle
permeable only to water adn the medulla has an ever increasing osmolarity
ascending limb of the loop of Henle
change in permeability; only permeable to salts and not water
increasing amounts are removed as it travels up
thicker diluting segment (cells lining the tube are larger)
Explain the diluting segment
cells are larger; contain large amounts of mitochondria, which allow reabsorption of Na+ and Cl- by active transport
Distal convoluted tuule
responds to aldosterone, which promoes sodium reabsorption
sodium ions are osmotically active particles so water will follow, concentating the urine
responsive to aldosterone and ADH
permeability increases--> water reabsorption
What are the functions of the kidneys?
control BP, blood osmolarity, and acid-base balance
What does aldosterone work on?
What does ADH work on?
alters permeability of collecting duct directly, allowing more water to be reabsorbed by making the cell junctions of the duct leaky
sensory cells present at the epidermal-dermal junction; connected to sensory neurons and are responsible for deep pressure and texture sensation within the skin
respond to light touch
respond to stretch
respond to deep pressure and vibration
muscles that contract in cold conditions causing hair to stand up
What does cardiac muscle have?
gap junctions that allow for flow of ions directly between cells
this allows for coordinated muscle cell depolarization and efficient contraction of cardiac muscle
gap junctions allow for progressive depolarization to spread via ion flow across the gap junctions between cells
contains mostly thin flimaents
contains the thick filaments in their entirety, including any overlap with think filaments
contains only thick filaments
Explain muscle contraction
- contraction starts at the neuromuscular junction, where the NS communicates with motor neurons
- The signal travels down neuron until it reaches the nerve teerminal, where acetylcholine is released into the synapse
acetylcholine binds to receptors on the sarcolemma, causing depolarization
Troponin and tropomyosin
calcium binds to troponin, causing a change in conformaiton of tropomyosin, allowing exposure of myosin binding sites
ATP bound to myosin causes what?
release of myosin from actin
if a muscle fiber is exposed to frequent and prolonged summation, it will have insufficient time to relax; the contractions combine, become stronger and more prolonged
fast twitch muscles form of energy?
have less mitochondria and rely on glycolysis and fermentation to make ATP under most circumstances
cyclindrical shafts called diaphyses that swell at each end to form metaphyses and that terminate in epiphyses
se spongy cores for more effective dispersion of force andpressure at joins; at internal edge is an epiphyseal growth plate, which is a cartilaginous structure and the site of longitudinal growth
a laer of soft tissue that secretes synovial fluid, which lubricates the movement of structures in the joint space
muscle that decreases the angle across a joint
increases or straightens this angle
moves a part of the body away from teh midline
moves part of body toward midline
population measure defined as the proportion of individuals in the population carrying the allele who actually express the phenotype
when 100% of individuals with the allele show symptoms
most but not all show symptoms of the disease
varying phenotypes despite identical genotypes
If expressivity is constant, then what?
all individuals with a given genotype express the same phenotype
Mendel's first law
genes exist in alternative forms called alleles
an organism has two alleles for each gene, one inherited from each parent
the two alleles segregate during meiosis, resuting in gametes that carry only one allele for any inherited trait
if two alleles are different, one is fully expressed and the other is silent
occur when a segment of DNA is copied multiple times in the genome
occur when a segment of DNA is reversed within the chromosome
occur when a segment of DNA is moved from one chromosome to another; small insertion mutations are considered frameshift mutations
occur when a segment of DNA from one chromosome is swapped with a segment from another
- flow of genes between species
- individuals from different species can mate to produce hybrid offspring, which can't reproduce
extreme case of genetic drift in which a small population of a species finds itself in reproductive isolation from other populations as a result of natural barriers, catastrophes, or other bottleneks that drastically and suddenly reduce the size of the population available for breeding
changes in the composition of the gene pool due to chance
loss of genetic variation that may cause reduced fitness of the population
intro of unrelated individuals into a breeding group
The bottleneck effect is a sharp lowering of a population's gene pool because of an environmental, or human-caused, change
the likelihood that two alleles are separated from each other during crossing over
roughly proportional to the distance between the genes on the chromosome
how often an allele appears in a populaiton
ex: if 75 alleles were dominate out of 100, there is a .75 frequency
Wat criteria must be met for the gene pool to be stable and evolution to not be occurring?
population is very large (no genetic drift)
mating is random
no migration of individuals into or out of the population
genes are equally successful at reproducing
modern synthesis model
adds knowledge of genetic inheritance and changes in the gene pool to Darwin's original heory
measure of an organism's success in teh population
altruism is a component of inclusive fitnesss that is helping others because it will increase your sucess
suggests that changes in some species occur in rapid bursts rather than evenly over ime
keeps phenotypes within a specific range by selecting against extremes
adaptive pressure can lead to the emergence and dominance of an initially extreme phenotype
two extreme phenotypes are selected over the norm
related concept of dirsuptiv selection that describes the rapid rise of a number of differnt species from a common ancestor that enables animals to occupy certain niches
prezygotic mechanisms include...
- temporal isolation (breeding at different times)
- ecological isolation
- behavioral isolation (lack of attraction)
- gametic isolation (fertilization not possible)
postzygotic mechanisms include...
- hybrid inviability
- hybrid sterility
- hybrid breakdown
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