Bio f4 chap 12 Flashcards
In your opinion, why is coordination crucial to humans?
- any changes that occur in the external environment or in the body can be detected and an appropriate response can be executed
Explain the role of the brain in body coordination.
- brain receives various types of information from the receptor
- it analyses, integrates and links the information together to form a meaningful overview
- after the information is processed, appropriate response will be determined
- effectors are directed to execute the response
State one difference between the functions of the somatic nervous system and the autonomic nervous system.
- somatic: controls all voluntary actions
- autonomic: controls involuntary actions
Explain why we cannot resist sneezing.
- an involuntary action
Why do synaptic knobs contain a lot of mitochondria?
- to generate the required energy needed for the transmission of nerve impulses
How are electrical impulses transmitted through synapses?
- through the synapse chemically (neurotransmitters)
Predict what would happen to the transmission of impulses if the neurone does not have a myelin sheath?
- the transmission of nerve impulses is slowed down because there are no Ranvier nodes
State the sequence of impulse transmission in the knee jerk reflex arc.
Receptor - sensory neurone - relay neurone in the spinal cord - motor neurone - effector
One example of reflex action is pulling the hand away form a hot object. Define the reflex action and state its importance.
- defined as a quick and automatic response that does not involve thinking
- protect ourselves from threatening situations and guarantees survival in the ever-changing environment
Differentiate between voluntary and involuntary actions.
- voluntary action: under conscious control
- involuntary action: an action we have no control over
Someone who loses a leg due to a certain disease will still feel pain in the area where the limb was amputated. Explain why.
- the presence of sensory neurones at the amputated part
- the neurotransmitters secreted by the sensory neurones at the amputated part trigger nerve impulses and are interpreted by the brain as pain
Explain how drugs effect the coordination of one’s nerves.
- drugs speed up or slow down impulse transmission at the synapse by obstructing the action of substances that transmit synapse
Who do doctors use drugs in the treatment of cancer patients who undergo chemotherapy?
- reduce nausea and pain of the patient
Explain why a drunk individual is not allowed to drive a vehicle.
- alcohol impairs the brain’s ability to estimate distance when driving and to coordinate
State three characteristics of hormones.
- secreted by a specialised gland known as the endocrine
- required in a small quantity only
- effect period is long
A pupil finds herself being followed by a van and suspects there is an attempt to kidnap her. In a state of panic, the pupil is able to run fast and far away from the van. Explain the ‘fight or flight’ in this situation.
- in a threatening or ‘fight or flight’ situation, the hypothalamus transmits nerve impulses directly to the adrenal medulla to secrete adrenaline and noradrenaline
- both hormones quickly act by producing the required response in a ‘fight or flight’ situation
- these include increased heartbeat rate, respiratory rate, blood pressure, blood glucose level, and metabolic activities
- the heart needs to pump more oxygen and glucose to the brain and skeletal muscles
- the brain must be very alert and prepared to move the body and the skeletal muscles need energy to fight or to run away quickly
- in a threatening situation, both the endocrine and nervous systems cooperate to produce an immediate response to face the threatening situation
- after the mechanism succeeds in controlling the threatening or ‘fight or flight’ situation, the body condition returns to normal
Goitre is a disease that causes the enlargement of the thyroid gland. In your opinion, why are goitre patients encourage to eat seafood?
- happens due to the failure of thyroid gland to produce sufficient thyroxine
- may result from a lack of iodine since thyroxine contains iodine
- seafood contains high iodine content
- eating a lot of seafood may be able to increase the body’s iodine content
Suggest a treatment for children with stunted growth due to growth hormone deficiency.
- the gene for human growth hormone was successfully inserted into Escherichia coli. This enables the mass production, isolation and purification of the hormone for commercial use.
- stunted children can be injected with this growth hormone
If the spinal nerve is cut at ventral root, what is the effect on the organ that is connected to it? Explain why.
- the motor neurone will not be able to convey information to the effector (such as muscles and glands)
- the effector will not be able to respond to the commands of the spinal cord
Explain why transmission of impulse through a neurone occurs in one direction only.
- after being secreted from the synaptic vesicles, neurotransmitters will move across the synapse, and fuse with the receptor of the next neurone
- impulse transmission takes place in one direction only
Explain the effects of stimulant drugs and sedative drugs on the transmission of impulse through the synapse.
- stimulants such as cocaine prevent the removal of the neurotransmitters that stimulate excitement
- this will produce an intense euphoric feeling followed by depression
- increase impulse transmissions that cause increases in the heartbeat and respiration rates
- depressants such as heroine will retard and slow down the activities of the nervous system
- slows down the production of neurotransmitters which will then reduce the rate of heartbeat and respiration
- individual will experience temporary excitement and satisfaction
Nora accidentally stepped on a nail. She screamed while holding on to her injured foot. Describe Nora’s reaction when she stepped on the nail.
- a sharp nail that pierces through the skin causes the sensory receptor in the skin to generate nerve impulses
- the nerve impulses are transmitted along the the sensory neurone to the spinal cord
- in the spinal cord, the nerve impulses are conveyed form the sensory neurone to the relay neurone
- from the relay neurone, the nerve impulses are transmitted to the motor neurone
- the motor neurone carries the nerve impulse from the spinal cord to the effector (muscle tissues) so the foot can be moved immediately
After tea time, Azman went to the playground to ride his bicycle. While riding his bicycle, Azman is conscious of his action. However, he is not conscious of what is happening to the food that he had just eaten. Describe why Azman is conscious of his action riding his bicycle but is not conscious of the food he had just eaten.
- his action involves a voluntary response under his conscious control (riding)
- digestion is an involuntary response which is beyond his conscious control
- the control centre involved in riding the bicycle is the central nervous system and involves the musculoskeletal system
- Azman has past experiences on how to ride a bicycle.
- this information is triggered in the motor area of the cerebral cortex
- since the information is triggered in the cerebral cortex, it is a conscious response
- the information is then transmitted to the effectors that is the skeletal muscles on the foot and arm through the motor neurone
- the contraction of the skeletal muscles enables Azman to ride the bicycle at his own well
- besides cerebral cortex, information on the body balance is also sent from the balance receptor in ears to the control centre
- the control centre involved in food digestion is the medulla oblongata and the muscles involved are the smooth muscles
- the presence of food in the digestive tract triggers impulses on the receptor and information is sent to the medulla oblongata
- this information is conveyed to the smooth muscles through the motor neurone
- the smooth muscles contract and relax in rhythm to produce a wave of peristalsis that will move the food along the digestive tract
- since the information does not reach the cerebral cortex which is responsible for voluntary responses, the perception of food peristalsis does not arise
How does the brain decide in determining how much energy is needed to lift a piece of paper compared to a book?
- makes decision based on past experiences
- it knows that a book is heavier than a piece of paper
- the brain stimulates a number of muscle fibres depending on the energy required
- some motor neurones are able to stimulate a few muscle fibres
- the motor neurones that are able to stimulate a large number of muscle fibres will produce more lifting force compared to the ones that stimulate a few muscle fibres
- in order to left a book, the brain will stimulate the motor neurones that stimulate many muscle fibres
