- Evolutionary biologists believe that the "fight or flight" response was crucial for the survival of many species throughout Geologic Time.
- Both the sympathetic and parasympathetic nervous systems are vital to our health and survival.
- The neural system of all animals is composed of highly specialised cells called neurons which can detect, receive and transmit different kinds of stimuli.
- When the "fight or flight" response has been activated of the autonomic nervous system called the sympathetic division controls this response.
What is human nervous system?
- The human nervous system is divided into two parts,
1. The Central Neural System(CNS)
2. The Peripheral Neural System(PNS)
- The CNS includes the brain and the spinal cord and is the site of
- information processing and control.
- The PNS comprises of all the nerves of the body associated with the CNS i.e., brain and spinal cord.
- The nerve fibres of the PNS are of two types :
1. Afferent fibres
2. Efferent fibres
- The PNS is divided into two divisions called;
a. Somatic neural system
b. Autonomic neural system
- The somatic neural system relays impulses from the CNS to skeletal muscles while the autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body. The autonomic neural system is further classified as;
(i) Sympathetic neural system
(ii) Parasympathetic neural system
To learn more about human nervous system: brainly.com/question/26348097
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Answer:
The forces acting on the box became unbalanced when the third student started pushing.
Explanation:
The horizontal forces, friction and applied, were balanced until more force was applied than friction. Mass can't increase or decrease.
Answer:
2. Van Leeuwenhoek
Explanation:
Hooke did discover it but the cells were dead!
It is the central vacuole
Answer:
1:2:0
Explanation:
If two recessive lethal alleles come together, they will be expressed and lead to the offspring's death. Let the dominant allele be S and the recessive allele be s. Here, the two individuals are heterozygous for it. So when they mate:
S s
S SS Ss
s Ss ss
1/4 have homozygous fominant genotype (SS), 2/4 have heterozygous genotype (Ss) and 1/4 have homozygous recessive (ss) genotype. Since 1/4 offspring have ss genotype, they will die. Hence, the usual 1:2:1 ratio has been modified here to only 1:2:0