Neurological System Flashcards
How many neurons are present in the human brain?
86 billion
Place the following species in descending order
1) Chimpanzee
2) Gorilla
3) Human
4) Elephant
4-3-2-1
What is the order of process of a nervous signal?
Reception -> treatment -> transmission
What is the structure of a cell membrane?
thin, elastic structure composed entirely of:
- lipid barrier (bilayer)
- Proteins
- Carbohydrates
What is the lipid bilayer impermeable to?
It is impermeable to water and the usual water-soluble substances but permeable to lipid-soluble substances
What are the two types of membrane proteins?
Integral proteins & peripheral proteins
Describe an integral protein.
Protrudes through the membrane, acts as pores and channels, substance carriers
Describe peripheral proteins.
attached to only one surface of the membrane (often attached to the integral protein). Act as enzymes, controller of transport channels
What are the two basic processes of transport?
Diffusion and active transport
Describe simple diffusion.
it requires no energy, molecules move through interstices of lipid bilayer (lipid-soluble substances) and through protein channels for water and lipid-insoluble molecules
Protein channels are selectively permeable to one or more specific ions or molecules based on:
- the diameter of the channel
- the diameter of the substance
- the shape of the channel
- the nature of electrical charges along the surface of the channel
What are the two types of gates that regulate the opening and closing of protein channels?
Voltage-gated channels: gate responds to electrical potential, participates in the generation of AP
Chemical-gated (ligand-gated) channels: channel responds to the binding of another molecule with the channel, participates in the synaptic transmission (receptor)
Describe the process of facilitated diffusion
Molecule diffuses by using a specific carrier protein, it enters the pore and binds to the binding point of the protein. A conformational change occurs so that the pore opens to the opposite side. At this position, the molecule is released.
What is the role of facilitated diffusion?
Carrying large molecules like glucose and amino acids
True or False. (simple diffusion) Diffusion rate speed is proportional to the concentration of the transported substance (i.e. the higher the concentration, the faster the rate of diffusion)
True, it is false for facilitated diffusion where the diffusion rate approaches a max when the concentration of the substance increases
What are the factors that affect the net rate of diffusion?
- Concentration difference (concentration gradient): from high concentration to low concentration
- Electrical Potential Difference: electrical charges of ions causes them to move across the membrane even though there is no concentration gradient
Define Active Transport
It requires energy. molecules or ions move across the membrane through a carrier protein against their concentration gradient and/or electrical gradient
What are the two types of active transport according to the source of energy used?
Primary Active Transport (energy is directly driven from ATP) & Secondary Active Transport (2 different substances are transported, energy driven from concentration gradient of one of the transported substances)
How many sodium and potassium ions are pumped in and out of the cell in the sodium-potassium pump?
3 Na+ pumped out
2 K+ pumped in
What does the Sodium-potassium pump establish inside the cell?
it establishes a negative electrical potential
What are the two substances transported in secondary active transport?
Principal & co-transported
Where does the energy required to move the substances comes from?
It is from the concentration gradient of the principal transported substance (gradient energy)
What are the two forms of secondary active transport according to the direction of diffusion of the two substances?
Symport (co-transport): the 2 substances move in the same direction
Antiport (countertransport): the 2 substances move in opposite direction
What is the main goal of secondary active transport?
To maintain homeostasis in cell
Example of Symport (glucose and sodium)
Na+ is the principal substance, glucose is the co-transported. Both substances move together into the cell
Example of Antiport ( Sodium & Calcium or hydrogen)
the principal and co-transported are located on opposite sides of the membrane.
The principal moves from outside to inside while the co-transported goes from the inside to the outside
True or False. Molecules are constantly kept with unequal concentrations inside and outside of the cell.
True
