Answer:
The statement that says the cranial meninges have three layers of the dura mater is false.
Explanation:
The meninges are protective layers located between the central nervous system and its bone protection, both at the level of the brain and the spinal cord. The brain and spinal cord are surrounded by three membranous layers (cranial meninges), these are the dura mater, arachnoid mater and the pia mater, they are located one below the other.
The dura mater is the outermost strong fibrous tissue layer, formed by two layers of which the outermost one is attached to the bone and represents its periosteum. The innermost layer joins the arachnoid membrane. In addition to being the outermost meningeal, the dura mater is the hardest and most condensed of the three we have. Attached in part to the skull, this membrane protects the brain and acts as a structural support to the entire nervous system by dividing the cranial cavity into different cells.
The arachnoid mater, located in an intermediate zone between dura and pia mater, through this meninge and the space between arachnoid and pia mater it’s where the cerebrospinal fluid circulates; and protects the central nervous system against injuries.
The pia mater is the most internal, flexible meninge and in the greatest contact with the structures of the nervous system. In this layer you can find numerous blood vessels that supply the nervous system structures.
The spinal meninges are inside the spinal canal and encase the spinal cord. They have the same basic structure as the cranial meninges, composed of three layers: the dura mater, the arachnoid mater and the pia mater.
Answer:
the correct sequence of the events happened during nerve impulse is (d): 2,1,4,3
Explanation:
Originally K+ ions remains inward the membranes while Na+ ions remains outward to maintain a resting potential of membrane.
Upon stimuli Sodium channels open on membrane and Na+ diffuses inward leading to the depolarization of membrane that is it becoming more positive due to Na+ and K+ ions.
To regain it polarized state or in repolarization state Potassium channels open and K+ begun to diffuse outward while Sodium channels gets closed and Na+ ions remains inside the membrane.
Potassium channels are not efficient as compared to Sodium Channels, so an excess amount of K+ion move outward so Hyperpolarization state achieved.
As the both ions are on the wrong side and will not be available for the next nerve impulse. Hence in Refractory period by the help of Na+/K+ pum, both ions move back to their original place and membrane achieve its resting membrane potential state.
Answer:
The Microscope
Explanation:
Before the 1600s, every living thing was a part of a two kingdom classification system derivative of binomial nomenclature. This was proposed by Linnaeus, a Swedish Naturalist, who split all living things into either the animalia or plantae kingdom. After the invention of the microscope however, a new detailed classification system was put in order to accommodate for microscopic life. This new system recognizes the existence of 6 kingdoms: eubacteria, archaebacteria, prostista, fungi, plantae, and animalia.
Compact fluorescent bulbs are a more efficient way to provide electrical light within homes and other buildings. These bulbs are one of the easiest ways to save money. According to GE, compact flourescent bulbs, or CFLs for short, use 70% less energy than a traditional, incandescent bulb and last up to 10 times longer than a standard incandescent bulb. As society pushes for improved efficiency, compact flourescent bulbs need to be carefully examined. Although these bulbs are more efficient, there are many problems with compact fluorescent bulbs.
The correct question with the options would be:
During which part of the cell cycle is DNA polymerase most active?
a. G1 phase of interphase
b. mitosis
c. S phase of interphase
d. G2 phase of interphase
e. cytokinesis
The correct answer is c. S phase of interphase.
The replication of the entire genome or the whole DNA occurs during the S-phase or also called synthesis phase. Therefore, the enzyme is DNA polymerase which carries out the replication of DNA shows its maximum activity. The DNA polymerase is active in various cell cycle checkpoints to detect the DNA damage but the repair action of DNA polymerase involves only a small region of DNA as compared to the whole genome during the S-phase.