In the light reactions, H2O goes in, and O2 goes out.
The conduction of nerve impulses relies upon the movement of positively-charged ions across the nerve cell membrane. The entry of sodium into the cell produces a wave of positive charge that travels down the length of an axon. Then chemicals called neurotransmitters are secreted out of the end of the axon onto the next nerve in the series (the postsynpatic nerve). This narrow space in between neurons is called the synapse. These neurotransmiiters released by the presynaptic nerve bind to receptors on the postsynaptic nerve. The binding of these receptors opens up channels in this second nerve's membrane that allow sodium ions to enter the nerve cell and initiate another wave of positive charge, and so on... The nerve signal can only move as fast as these ions and neurotransmitters can diffuse to generate this process.
<span>As a professional athlete repeats a given activity many times over, the nerve cells "upregulate" their receptors, meaning that they produce additional receptors to put in the membrane. This is just a natural reaction to the nerve being repeatedly stimulated in the same way over and over. When neurotransmitter is secreted from the presynaptic neuron, there are more receptors on the postsynaptic neuron for it to bind, more channels open up, more ions enter in a shorter time and build up positive charge to create the impulse faster, and so the overall effect is faster. </span>
<span>Additionally, there are sheaths of fatty tissue (called myelin) that insulate the charge in the neuron and allow it to be conducted faster. As people age, these sheaths can start to degrade, making the nerve cell more "leaky" and causing the impulse to be conducted more slowly. </span>
Answer:
A. 3
B. 4
C. 5
D. 6
E. 2
F. 1
Explanation:
1. Integumentary system.
This is an organ system that consists of hair, skin, nails and exocrine glands with receptors that senses the outer stimulus and environmental conditions, through homeostasis maintain stability of the internal environment.
2. Nervous system.
It receives sensory information and signals, convert them to nerve impulses that are transmitted to the body and brain via the spinal cord using nuerons and axons. It also intergrates, retains and analyses information in the brain.
3.Endocrine system.
Secretes hormones and chemicals in response to stimulus from the nervous system to maintain balance using feedback loops i.e, negative and positive.
4. Lymphatic system.
Part of the immune system that consist of vessels that carries lymph, cleaning the blood by filtering lymph with foreign particles into the lymph node.
5. Urinary system.
Used to eliminate waste from the body, regulates blood pressure, volume and pH. It also used to retain electrolytes and metabolites.
6. Respiratory system.
Used for gaseous exchange using the blood, heart and lungs. Air enters the lungs, transported by blood and is pumped by the heart to all body parts where oxygen is dropped, carbon dioxide is collected by the veins to the lungs and released to the atmosphere.
Explanation:
Biological hazards include microorganisms such as bacteria, viruses, yeasts, molds and parasites. Some of these are pathogens or may produce toxins. A pathogenic microorganism causes disease and can vary in the degree of severity
Answer: The correct answer is A) Stratum basale.
Sudoriferous glands are also called as 'Sweat glands'. They are exocrine glands as they secrete their substances through the duct. They are tiny tubular glands with the secretory unit which is present in the dermis or subcutaneous tissue, and a duct which opens on the surface of the skin. Their primary role is regulation of body temperature as by sweating, body heat is lost.
During fetal development, sudoriferous glands develop from the Stratum basale. It is the deepest layer of the epidermis. It is made up of a single layer of cells which are resting upon the basement membrane, a layer present between dermis and epidermis.
Thus, sudoriferous glands are derived from Stratum basale during fetal development.
