There are nearly 100 viruses of the herpes group that infect many different animal species.
Official name of herpesviruses that commonly infect human is Humans herpesvirus (HHV)
herpes simplex virus types 1 (HHV 1)
Herpes simplex virus type 2 (HHV 2)
Varicella-zoster virus (HHV 3)
Epstein-Barr virus, (HHV 4)
Cytomegalovirus (HHV 5)
Human herpesvirus 6 (HHV 6)
Human herpesvirus 7 (HHV 7)
Human herpesvirus 8 (HHV 8) (Kaposi's sarcoma-associated herpesvirus).
Herpes B virus of monkeys can also infect humans
hELMINTHS#corona virus#Aspergillosis#BUGANDO#CUHAS#CUHAS#CUHAS#CELL MEMBRANE TRANSPORT#PHYSIOLOGY#BODY FLUIDS#RENAL PHYSIOLOGY#
Day 5a-TRANSPORT ACROSS THE CELL MEMBRANE (5)b.pptx
1. TRANSPORT ACROSS THE
CELL MEMBRANE
CONTINUED FROM PREVIOUS SLIDE
1
DR.HAMISI MKINDI,MD.
TO DOWNLOAD CONTACT: hermyc@live.com
2. Cell Membrane
• Structure
• Function
Passive Transport
• Simple Diffusion
• Facilitated Diffusion
Active Transport
• Primary
• Secondary
Endocytosis and
Phagocytosis
2
10. The Na-K pump is the most important
primary active transporter in animal cells
•It is located in the plasma membrane
•Uses energy of ATP to extrude Na+ and take up K+
•Utilizes about a third of ATP consumed by body
10
11. The Na+-K+ pump mechanism
•Pumps 3Na+ outward of cell membrane
•Pumps 2K+ from outside to the inside
at the same time
11
13. In animal cells, it is the only primary
active transport process for Na+.
• Also the most important primary active K+
transport mechanism
13
14. In cells throughout the body, is
responsible for maintaining
• A low [Na+]i and a high [K+]i relative to ECF.
•In most epithelial cells, the Na-K pump is
restricted to the basolateral side of the cell.
14
16. A hallmark of the Na-K pump is that
it is blocked by cardiac glycosides,
•Examples of which are ouabain and digoxin;
•Digoxin is widely used cardiac conditions
16
20. Most if not all cells have a
primary active transporter at
the plasma membrane that
extrudes Ca2+ from the cell.
20
21. Calcium ions are normally maintained at
extremely low concentration in the ICF
•This is achieved by two active calcium pumps
•At the cell membrane (PMCA), the other
•Ca++ pump in the sarcoplasmic reticulum.
21
27. At two places in the body, primary active
transport of hydrogen ions is important:
•In the gastric glands of the stomach and
•In the renal distal tubule and collecting ducts.
•These segments achieve very high [H+] gradients.
27
28. There are two major types of
hydrogen ion pumps the:
• H+-ATPase pump (V-ATPase proton pump)
• H+/K+ -ATPase pump (P-Type ATPase)
28
29. In the parietal cells an
H-K pump extrudes H+
at the apical membrane.
29
35. In secondary active transport
the energy is derived from
•A concentration gradient created by
•Active transport of another substance
35
36.
37. When a large [sodium] gradient is
created by primary active Na+ transport
• Na+ increasingly attempts to enter the cell
• Dragging with it other substances (Symport) OR
• Induce another substance move out (Antiport).
37
39. Secondary active transport can
therefore be divided into
•Co-transport (Symporter)
•Counter-Transport (Antiporter)
39
40. GLU and many AA are transported into
most cells against concentration gradients
• The mechanism of this is entirely by co-transport
• Na+GLU co-transport is good example of symporter.
40
41. The carrier protein has
two binding sites one
for Na+ and one for
GLU.
When both Na+ and
GLU become attached,
sodium and glucose are
transported to the
inside of the cell at the
same time
HIGH [Na+]
LOW [Na+]
41
42. Sodium-GLU co-transport occurs
especially through the epithelial cells
•In intestinal tract and
•The renal tubules of the kidneys
•To promote absorption of these substances
42
49. Sodium-Calcium counter-transport occurs
through all, or almost all, cell membranes.
• With sodium ions moving to the interior and
• Calcium ions the exterior bound to same protein
• This is in addition to primary active transport
49
50. Sodium-Hydrogen counter transport
occurs in several tissues especially.
•In the proximal tubules of the kidneys,
•Sodium ions move from the lumen while
hydrogen ions are secreted into the lumen.
50
52. In both primary and secondary active
transport
•Transport depends on integral (carrier) proteins,
•In active transport, the carrier protein, imparts
energy to move a substance against gradient.
52
54. Endocytosis is a cellular process in which
substances are brought into the cell.
•The material internalised is surrounded by
•An area of plasma membrane,
•Which then buds off inside the cell.
54
56. Very large particles enter the cell by a
specialized function of endocytosis.
•The principal forms of endocytosis are
•pinocytosis and
•phagocytosis.
56
57. PHAGOCYTOSIS ("CELL
EATING")
• Is the process by which
bacteria, dead tissue,
or other bits of
microscopic material
are engulfed by cells
PINOCYTOSIS ("CELL
DRINKING")
• Is a similar process
with the vesicles much
smaller in size and the
substances ingested
are in solution.
57
59. The cell is the basic unit of life
•It has a cell membrane; which separates it
•From its surrounding environment
•Made up of a bilayer of phospholipids
59
60. 60
Cell membrane allows
lipid soluble substances
to enter or exit the cell
by simple diffusion
It has proteins that
provide mechanisms for
water and water soluble
substances to enter or
exit the cell
61. There are two major classes of membrane
transport proteins:
• Channel proteins: provide passage of water/ions
• Carrier Protein; that provide
• Active transport mechanisms
• Passive transport mechanisms
61
62. Passive carrier proteins facilitate the downhill
transport of substances across membranes.
• An example of a carrier protein that carries out passive
transport is the glucose transporter.
• Allows glucose to enter cells
• Allows glucose to exit liver cells
62
63. Active transport provides for transport of solutes
against electrochemical gradients. These include
• ATP-driven ion pumps
• Coupled Transporters (secondary active transporters).
• Symport
• Antiport
63
64. Active transport at the cell membrane
provides
•Maintaining composition and the volume of ICF
•Creating and maintaining membrane potentials
critical for excitable tissues
64
The figure in this slide shows a calcium pump and calcium exchanger that keep intracellular calcium concentration low. The Calcium pump exchanges one H+ for one Ca2+ for each molecule of ATP that is hydrolyzed.
The figure shows an IP3 sensitive ligand-gated Ca2+ channel located in the membrane of the endoplasmic reticulum. Interaction of IP3 with its receptor results in passive efflux of Ca2+ from the endoplasmic reticulum causing a rapid rise in the free cytoplasmic Ca2+ ion concentration.
Dephosphorylation of IP3 terminates the release of Ca2+ and triggers an ATP-fueled Ca2+ pump (SERCA) which moves the Ca2+ back into the endoplasmic reticulum. SERCAs appears to transport a H+ in exchange for a Ca2+ ion.
In the parietal cells of the gastric gland, an H-K pump (HKA) extrudes H+ across the apical membrane into the gland lumen. The H-K pump mediates the active extrusion of H+ and the uptake of K+, all fueled by ATP hydrolysis, probably in the ratio of two H+ ions, two K+ ions, and one ATP molecule.
The slide shows in an alpha intercalated cell the two types of proton pumps the H+-ATPase pump and the H+/K+ -ATPase pump both located in the apical (luminal) membrane.
This figure shows a typical secondary active transport mechanism for glucose. It can move glucose against its own concentration. The primary sodium potassium extrudes sodium ions thus reduces the concentration of sodium within the cell. This creates a concentration gradient along which extracellular sodium can get into the cell. When sodium enters the cell it drags with it a glucose molecule using the energy created by the sodium potassium pump making this secondary active transport