lecture 1 Flashcards
Physiology of Cell Membranes
what comprises the cell membrane?
phospholipid bilayer, proteins, intercellular connections
how is a phospholipid comprised?
glycerol backbone (hydrophilic) and two fatty acid tails (hydrophobic) and they are oriented so that the polar heads face opposing directions
how does cholesterol help the membrane?
provides the membrane with rigidity and flexibility and can easily flip sides
name the two types of proteins located in the cell membranes
integral proteins and peripheral proteins
what are the functions of the integral protein?
1) anchored and imbedded through hydrophobic interactions
2) can span the membrane
3) include ion channels, transport proteins, receptors, guanosine 5’-triphosphate
what are the functions of the peripheral protein?
1) not imbedded in the membrane
2) not covalently bound to membrane components
3) loosely attached to membrane via electrostatic interactions
what are the other functions of proteins besides being pores?
they also aid in muscle contraction through which actin ties itself to anchoring protein via spectrin dimer
what is used to bind actin to anchoring proteins?
spectrin dimers
what happens if a baby is born without anchoring bridges that link protein to actin?
baby has trouble with activities that require muscle movements and cells begin to rupture and muscles atrophy
what is hereditary spherocytosis?
spectrin is absent either not present or defective and leads to deformity of reb blood cells, the RBCs are not biconcave moreso rounded in nature, and so RBCs cannot maintain membrane integrity in addition to not being able to move through the capillaries
what happens as a result of hereditary spherocytosis?
osmotic fragility (increased loss of RBCs) and increased work by spleen removing them from circulation
signs/symptoms of hereditary spherocytosis?
fatigue
what are the red blood cells called before becoming fully mature?
reticulocytes produced from the bone marrow
what percentage of reticulocytes are comprised in the body? Percent with someone who has hereditary spherocytes? Why?
1%; 2-3.5%; reticulocytes keep puncturing because of their shape and the bone marrow works harder to replenish the loss of RBCs
what is known as the powerhouse of the cell, site of ATP of production
mitochondria
this cell component is responsible for the packaging and secreting of proteins?
golgi apparatus, keep in mind that it also modifies different parts of the cell like lysosomes to get rid of unwanted cellular material. If not able too, than developmental issues can affect the cell
this part of cell is responsible for housing genetic material?
nucleus
This part of the cell is used in the translation process to produce proteins
endoplasmic reticulum
when proteins are produced using this pathway continuously and unregulated
constitutive pathway
when proteins are produced in this pathway and secreted by a hormonal or neural signal
regulated pathway
this is a type of vesicle found inside the cell that contains hydrolytic enzymes
lysosomes
how does a cilium function?
comprised of microtubules and protein used to move them in unison. This is accomplished by dynein arms
what happens if dynein arms are absent? what is this medical condition called?
if in the lungs, you have a defect in the dynein arms this can promote mucus buildup; Kartagener Syndrome
what is kartagener syndrome?
a rare, ciliopathic, autosomal recessive genetic disorder that causes defects in the action of cilia lining the respiratory tract (lower and upper, sinuses, Eustachian tube, middle ear), fallopian tube, and flagella of sperm cells.
where else can dynein arms be found?
along our axons containing a tubular system found in our neurons sending signals (NTs) to and from the brain via pathways using microtubules from cell to synaptic terminals using dynein and kinesin
considering Kinesin is found along the axon, what direction does it travel.
it transports NTs from the body to the axonal terminal from the minus to plus direction
also considering that dynein is found along the axon too, what direction does it travel?
it moves along the axon form the plus to minus end. It moves toward the cell body.
Why is this particular dynein, found in the axon, important?Name one?
because if the animal bites, the virus is collected by the dynein and moved closer to the CNS. This causes the CNS problems; herpes, shingles
What is Tay Sachs Disease?
fatal genetic lipid disorder where you have accumulation of ganglioside GM2 buildup in the nerves and brain. Caused by insufficient activity of enzyme beta-hexosamidase A found in Lysosomes to biodegrade acidic materials called gangliosides, made and biodegraded early in life. Some S/S include red retinas, muscle atrophy, paralysis, dementia
What absent enzyme is responsible for Tay Sachs disease?
enzyme beta-hexosamidase A
where is the mutation of the enzyme beta-hexosamidase A located that prevents it from being made?
The HEXA gene on the long (q) arm of chromosome 15 position 24.1
what is Gaucher disease?
an autosomal recessive disease resulting in the accumulation of a fatty substance called glucocerebroside, a byproduct of the RBC cycling. Generally resulting from intermarrying from a small pool of genes
what is the most prevalent lysosomal storage disorder
gaucher disease
what absent enzyme is responsible for Gaucher disease?
glucocerebrosdiase
the accumulation of this type of fatty acid is responsible for Gaucher Disease?
glucocerebroside
name some S/S of Gaucher disease?
anemia, fatigue, easy bruising and bleeding; mild moderate and severe types and depending on type patient can asymptomatic and managing is possible. More neuro problems if severe
what is endocytosis
taking in extracellular material into the cell either in small or big pieces and vesicles coated in clathrin to let cell know it is foreign
name the different types of epithelial cells
tight junctions, gap junctions, adhering junction and desmosome
what is tight junction?
form a watertight seal that block anything from in or out, found in the bladder, intestines, kidney
what is desmosome?
join two cells at a single point and prevent fluid from circulating around sides of the cell and found in the skin or intestinal epithelium. Help cell to stay in place
what is a gap junction?
small tunnels that connect cells facilitating movement of small molecules and ions between cells and found in smooth muscle allowing the fibers to contract as a unit, osteocytes
what is an adhering junction ?
anchor cells together
