True.
Circumcising is usually done due to religion or beliefs of the parents such as people who are Jewish. It was a big thing a while back as they believed it looked batter, that phase has since passed.
Axons are long nerve processes which carry nerve impulses from the Soma to other neurons, they vary in length but can become almost as long as half of the human body.
The soma (body) of the neuron contains the nucleus which acts as the cell's control centre, these contain many small neurofibrils which project from the nucleus into the dendrites.
Dendrites are short, thick processes which branch out of the soma in a tree like manor. They conduct nerve impulses to the soma.
The three categories of neurons:
Afferent (Sensory) Neurons have the dendrites connected to receptors such as the eyes, ears etc. These receptors change the information they receive into electrical impulses that are transmitted to other neurons. In sensory neurons the axons are connected to other neurons.
Efferent (Motor) Neurons have the dendrites connected to other neurons, the axons are connected to effectors. Effectors are either glands or a muscle cell that is the receiving end of the nerve impulse. The nerve, when excited will cause the effector to react (move, contract, or secrete etc).
Internuncial Neurons have both the dendrites and the axons are connected to other neurons. They are sometimes referred to as connector neurons.
Internuncial neurons are found throughout the body, but especially in the spinal cord and brain.
Properties and characteristics of Neurons:
Normally the electrical impulses (messages) travel through a neuron in only one direction.
The axon may be surrounded by a 'coat' of lipids (fats) and proteins known as the myelin sheath which acts as an insulator.
Neurons are specialist cells that have lost the ability to reproduce themselves. Once the soma of a neuron has died the entire neuron dies, and can never be replaced.
Repair of damaged neurons only occurs in myelinated neurons.
white matter are coloured by myelin, consisting of many neurons supported by neuroglia.
grey matter is soma and dendrites or bundles of unmyelinated axons and neuralgia.
A) Hypertonic environment
B) Lower pH
C) Depletion of nutrients
D) Lower osmotic pressure
Answer:
A) Hypertonic environment
Explanation:
A hypertonic environment or solution contains more solute than solvents, that is, the solution in the environment has more dissolved particles, such as salt or sugar. Microorganisms are unlikely to survive in a hypertonic solution as water would be drawn out of the ells of the mircoorganisms, causing their cells to shrink.
Salts and sugars are used in preserving foods as they create a hypertonic environment that is unfavorable to bacteria and fungi that cause food spoilage.
