physiology (active and passive transport)

Question 1

Uniport

Answer 1

transports 1
substance in 1
direction
(Ca++ pump)

Question 2

Symport

Answer 2

transports 2 substances
in 1 direction
(glucose & Na+ from intestinal
lumen into the cells).

Question 3

Antiport

Answer 3

transports 2
substances in 2
directions
(Na+- K+ pump)

Question 4

Primary active transport

Answer 4

Na+ / K+ pump

a. alpha subunit:
* An ATP binding site.
* 2 K+ binding sites on
the outer side.
* 3 Na+ binding sites
on the inner side.
b. beta subunit has:
ATPase activity →
breaks ATP into ADP +
P + energy.

Question 5

Importance of Na+/K+ pump:

Answer 5

• Maintains a high extracellular Na+ & a high
  intracellular K+
• Electrogenic pump (1 extra +ve ion is pumped
  out).
  It controls the cell volume (prevents cell
  rupture)

Question 6

Secondary active transport

Answer 6

Example: glucose transport 2ry to the active
transport of Na+

Question 7

A] Cells communicate with each other via chemical messengers through

Answer 7

1)intercellular Gap Junctions.
2)Neural
3)Endocrine communication.

Question 8

Intercellular Gap Junctions

Answer 8

a chemical substance passes
directly from cell to cell

Question 9

Paracrine communication

Answer 9

hormone → diffusion
in ISF → reach near cells

Question 10

Autocrine communication:

Answer 10

hormone → direct
action on the cell that produces it.

Question 11

Chemical messengers exert their intracellular effects through

Answer 11

1. Opening of certain channels.
2. Increase cyclic AMP.
3. Increase Ca++ in the cytoplasm.

Question 12

Spinal motor Neuron is composed of

Answer 12

1. Soma
2. Dendrites
3. Axon (Nerve Fiber)
4. Axon terminals

Question 13

Soma

Answer 13

cell body → processing center

Question 14

Dendrites

Answer 14

receive signals from other neurons.

Question 15

Axon (Nerve Fiber)

Answer 15

→ conduct the signal from axon
hillock to nerve endings (terminals)

Question 16

Axon terminals

Answer 16

synaptic Knobs → vesicles →
neurotransmitters → transmit signal to next cell

Question 17

A-fibers nerve

Answer 17

Diameter: 2-20 µ
Rate of conduction :20-120 m/sec
Example :Somatic motor
Nerve Conduction
Depressed by:
Pressure

Question 18

B-fibers

Answer 18

Diameter:1-5 µ
Rate of conduction:5-15 m/sec
Example: Preganglionic autonomic
Nerve Conduction
Depressed by: Hypoxia

Question 19

C-fibers

Answer 19

Diameter: less than 1 µ
Rate of conduction:0.5-2 m/sec
Example: Postganglionic autonomic .
Nerve Conduction
Depressed by:Local anesthesia.

Question 20

Voltage gating

Answer 20

respond to changes in membrane
electric potential, (Na+ channels).

Question 21

Ligand gating

Answer 21

open or close when bound to
chemical substance