CHAPTER-7 Control and coordination

Explanation:

The gap between two nerve cells is called a synapse. Most synapses are chemical, these synapses communicate using chemical messengers. At the end of the axon, the electrical impulse sets off the release of chemicals. These chemicals cross the gap or synapse and start an electrical impulse in the dendrite of the next neuron.

Explanation:

Cerebellum is located at the back of the brain which helps to maintain the posture and equilibrium of the body. The cerebellum maintains the postural adjustments in order to maintain balance. The cerebellum is also responsible for muscle control, including balance and movement. It also plays a vital role in other cognitive functions such as language processing and memory. Problems with the cerebellum can lead to coordination difficulties, fatigue, and some other challenges.

Explanation:

The smell of the agarbatti(incense stick) is detected by the olfactory receptors that are present in our nose. These olfactory receptors will send the signal to the olfactory lobe which is present in the forebrain and it will respond to the information.

Explanation:

In a reflex action, the brain plays no part. The spinal cord will react without thinking about how to respond to the stimuli, which is in charge of these automatic actions. There will be no meaningful response in the brain.

Explanation:

The hormones present in the plant are called phytohormones. These are the chemical substances that will control all aspects of plant growth such as flowering, height, development of plants, and their lifecycle in the environment.

The types of phytohormones are-  auxins, gibberellins, cytokinins, abscisic acid & ethylene.

Explanation:

Auxin is the hormone that is present in the plant and will promote the growth of the plant. Auxin promotes the cell growth and elongation of the plant. In the process of elongation, auxin alters the plant wall plasticity and makes it easier for the plant to grow upwards. Auxin regulates numerous developmental processes in plants including cell expansion, root initiation, vascular tissue differentiation, and bud and flower growth.

Explanation:

Auxin is a plant hormone that will be synthesized at the tip of the shoot. This will help the cell to grow longer. When a tendril will come into contact with a support, the auxin will stimulate faster growth of the cells on the opposite side so that the tendril forms a coil around the support.

Explanation:

Take two glass beakers and label them A and B. In a beaker, add some moist soil and plant a tiny seedling. In a beaker, B adds half moist soil and half dry soil and plants a similar seedling, and places a clay pot inside the soil. Now water the soil in beaker A daily and uniformly and do not water the soil in beaker B but put some water in a clay pot. Let the plants grow.  After a few days, we may notice that the roots of the seedling in beaker A are straight and the root of the seedling in beaker B grows towards the side of the clay pot containing water. The root of the seedling in beaker A gets water from both sides whereas the roots of the seedling in beaker B get the water oozing out from the clay pot. Therefore, in beaker B the roots of the seedling will end towards the source of water. This shows that the root of the plant always grows towards regions of water if there is a source of water nearby, in other words, the root of the plant is hydrotropism.

Explanation:

Chemical coordination in multicellular organisms takes place through the special chemical substances called hormones that are produced by the endocrine glands. These chemical substances will reach all the cells of the body and bring the desired changes that are instructed by the brain and spinal cord.

Explanation:

The consumption of iodized salt is advisable because the thyroid gland needs iodine to produce thyroxine hormone. Thyroxine is a hormone that controls all the metabolic activities of our body like the metabolism of carbohydrates, fats, proteins, etc.  Iodized salt will also help to regulate heart rate and blood pressure. It also helps to burn the extra fat deposits that could lead to heart disease. The lack of iodine in the diet will cause a deficiency of thyroxine hormone which will cause a disease called goiter.

Explanation:

Adrenaline is a stress hormone that is secreted by the adrenal glands. When the adrenaline is secreted into the bloodstream our heartbeat increases so that more oxygen is supplied to our muscles. Adrenaline hormone will help to regulate our metabolism, immune system, and blood pressure and allows the entry of more glucose into the blood and also responses to stress and other essential functions.  The blood supply to the digestive system reduces due to the contraction of the mussels around the small arteries in these organs. This diverts blood to our skeletal muscles. The breathing rate will also increase because of the contraction of the diaphragm and rib muscles.

Explanation:

Diabetes is a metabolic disorder caused by high sugar levels in the blood. Insulin is a hormone secreted by the pancreas that helps to regulate our blood sugar levels. The decreased secretion of insulin will result in an increase in blood sugar levels. This may cause many harmful effects on our bodies. To treat the harmful effects of increased levels of blood sugar, diabetic patients are treated by giving injections of insulin.

Explanation:

Cytokinin: Cytokinins are a group of plant growth regulator hormones that are basically involved in performing cell division in plant roots and shoot systems. Cytokinins promote the growth of the cells and development, differentiation, and shoot initiation, affecting apical dominance and delay in leaf senescence, nutrient uptake, phyllotaxis and vascular gametophyte, and embryonic development. These hormones are found in complex plants, mosses, fungi, and bacteria. Cytokinins help in increasing cell division by maintaining protein production which is important for the mitosis process

Explanation:

Synapse: Synapse is defined as the point of contact between the terminal branches of the axon of one neuron with the dendrite of another neuron. The two neurons will communicate through this junction. The production of neurotransmitters will help in this communication. There are two neurons involved in a synapse. Synapses most often form between axons and dendrites and consist of presynaptic neurons, synaptic cleft, and postsynaptic neurons. Based on its function there are electrical synapses and chemical synapses.

Explanation:

The biggest part of the brain is the cerebrum is located inside the skull at the top front of our head which is responsible for thinking and it also controls voluntary muscles. The human brain serves as the nerve system command center. Thought, memory, emotion, touch pain, motor skills, vision, taste, temperature, and hunger all are controlled by the brain. It also maintains our posture, and capability to talk, walk, eat and drink. It takes the information from our sensory organs and sends it to the muscles.

Explanation:

Receptors are present in all parts of the body like the ear, nose, skin, tongue, and eyes. They detect the signals from the environment and then send them to the brain in the form of electrical signals. If these receptors are damaged then they will not detect the input which may lead to harm to the body. For example, smell is detected by the olfactory receptors. If these receptors do not work properly, then the information obtained from the environment will be delayed to reach the spinal cord or the brain which may cause harm to the body. Another example is if the skin burns the skin receptors will not respond to the touch stimuli, as the skin is desensitized.

Explanation:

The nerve cell or neuron is called the functional unit of the nervous system. There are 3 parts in the nervous system :(a) Cell body: The cell body preserves the structural integrity of the neuron, houses the genetic material, and supplies energy to drive activities. Cytoplasm, cell organelles, and Nissl’s granules are all found in the cell body.

(b)Axons: The axon is a branching fiber with a long distal end.Each branch ends in a synaptic knob, a bulb-like structure that houses synaptic vesicles which contain neurotransmitter molecules. Neurons can be unipolar, bipolar, or multipolar depending on the number of axons and dendrites. Axons have two varieties: myelinated and non-myelinated.

(c)Dendrites: These are short fibers that branch out from the cell body repeatedly and also include Nissl’s granules.D dendrites can transmit impulses toward the cell body.    

Function: Neurons are the structural and functional unit of the nervous system. They are also responsible for receiving sensory input from external sources and sending motor commands to our muscles. The important function of neurons is to carry information in the form of electrical signals which are called nerve impulses. The cells receive a stimulus to send it to the spinal cord and to the brain and then carry the message from the brain to the target organ.

Explanation:

Phototropism is the movement with respect to the growth of plants toward the sunlight. The leaf tips and stem tips have a hormone called auxin which shows positive phototropism whereas the roots of the plant show negative phototropism. The secretion of hormone auxin is more on the opposite side of the plant where light doesn't fall and shady.

Explanation:

In case of spinal cord injury:

a. All involuntary actions will get disturbed

b. The reflex actions will also be disturbed because reflexes are located in the spinal cord. The signals coming from the receptors and the signals sent to the effectors will be disrupted, as both these signals meet in a bundle in the spinal cord, so in case of spinal cord injury both these signals may get disrupted. Therefore quick response is required to safeguard the body will not take place.

Explanation:

In plants, chemical coordination occurs with the help of plant hormones or phytohormones which are secreted by the plants. These hormones help to regulate the growth and development of plants. They also help to regulate the various metabolic activities of the plants. In meristematic regions, where the division takes place these stimuli cells will secrete hormones. These hormones will identify the information by stimulating other nearby cells and communicating the information.

Explanation:

An organism requires a control and coordination system  for the following functions:

a.  To protect the body of organisms from harmful changes in the environment.

b. It is required to control the speed of voluntary and involuntary actions.

c. There are various organs and organ systems present in organisms. These organ systems must be carefully controlled and coordinated for the survival of the organism.

Explanation:

The developing movement which is made by the plants in order to contact a solid object is called thigmotropism. When the tip of the tendril comes in contact with some uneven surface the tendrils will coil around them for support. Thigmotropism is when a plant responds to a movement or touch from other stimuli around it, This type of stimulus is also called a contact stimulus. There are two types of hormones that respond to the stimulus: auxin and ethylene. These two hormones play a major role in the growth and orientation of the plant.

Explanation:

The plant hormone called auxin is synthesized at the tip of the shoot of the plant. This hormone will help the cells to grow longer. This hormone will stimulate the growth when a tendril comes in contact with a support, this is the reason why the tendril forms a coil around the support.

Explanation:

Dorsal view of thyroid and parathyroid.

Thyroid: It is a ductless endocrine gland that resembles the shape of a butterfly and is situated in the front portion of the neck. The thyroid is one of the largest endocrine organs in the human body. The thyroid plays a major role in body metabolism, growth, and development of our body. It regulates our body function by releasing the correct amount of hormones into the bloodstream.

Parathyroid: These are small endocrine glands that are situated below the thyroid glands in the neck. These glands release parathyroid hormones which help to regulate the calcium and phosphorus levels in the blood.

Explanation:

There are two hormones that help in breastfeeding: prolactin and oxytocin.

Prolactin is a hormone that is secreted by the pituitary gland and is located at the base of our brain. Prolactin helps to grow the size of the breast and produces milk during pregnancy and after childbirth.

Oxytocin; It is also called milk ejection hormone, it is also produced more quickly than prolactin hormone and appears to have a calming effect on the mother. The Oxytocin reflex is also called as letdown reflex or the milk ejection reflex. It helps to secret the milk which is already present in the breast to flow for the current feed and helps the newborn to get the milk easily.

Explanation:

1. Insulin from P-cells of islets of Langerhans.

2. Glucagon from a-cells of islets of Langerhans.

Pancreas plays a vital role in maintaining normal blood sugar levels by producing hormones called insulin and glucagon. When the glucose level in the blood increases the insulin hormone will help to reduce the glucose level in the bloodstream. It also helps to convert glucose into glycogen in the liver and muscles.

 Glucagon is a hormone released by our pancreas when glucose levels are reduced in the bloodstream. It helps to increase blood sugar levels and helps to prevent them from dropping too low which may cause harm to our bodies.

Explanation:

Progesterone is a hormone that is mostly produced by the ovaries and plays a vital role to get a woman pregnant and also helps to maintain a healthy pregnancy. It also helps the uterus to get ready to accept and maintain the fertilized egg.

Explanation:

Abscisic acid is a plant hormone that is called domain. These hormones promote dormancy in buds, seeds, and stems. Abscisic acid will also provide dormancy in stressful conditions like drought and floods and protect the seeds from unfavorable situations. This hormone will also promote the growth and development of plants and protects them from certain pathogens, bacteria, and viruses.

Explanation:

A-dendrite, B- axon.

Explanation:

In the region of the synapse. Electrical impulses will stimulate and releases certain chemical neurotransmitters from the presynaptic knob or button of the axon terminal. Acetylcholine is a neurotransmitter that will come in contact with a chemoreceptor which is the site of the postsynaptic membrane present in the next neuron and then generates a fresh impulse.

Explanation:

Thyroxine Functions of thyroxine:

1. It helps to regulate the metabolic rate in the human body.

2. It helps to stimulate the metabolism of carbohydrates, proteins, and fats in the cells which helps to produce energy in the body.

3. It promotes bone health and aids digestion

4. It plays a vital role in heart function and brain development.

Explanation:

The consumption of iodized salt will help our thyroid glands to synthesize thyroxine hormone which is required to regulate our heart rate and blood pressure. Iodized salt also promotes the hydration levels in our body and thus maintains the balance of electrolytes.

Explanation:

Plant hormones are the signal molecules that are produced within the plant that appears in extremely low concentrations. Plant hormones are also called phytohormones which are chemicals produced by plants that help to regulate the growth and development of the plant and also help in the reproductive activity of the plant, longevity, and even death of the plant.   

The four plant hormones are auxin, gibberellins, cytokinins, and abscisic acid.

1. Auxin and gibberellins promote the growth of the plant

2. Abscisic acid will inhibit the growth of the plant

3. Cytokinins will promote the cell division

4. Auxin will promote the growth of a tendril around support.

Explanation:

A-Pons: It's a part of our brainstem that links our brain to our spinal cord. It also influences our sleep cycle and also manages pain signals.

B-Medulla oblongata: It is the bottom part of our brain that controls our heartbeat, our breathing pattern, and our blood pressure.

C-Cerebellum: It helps to maintain our posture, the toning of our muscles, and coordination and also helps to maintain the equilibrium of the body.

Explanation:

Tendrils do not have sensory structure but still, they have the capacity to find support just like humans grope in the dark in order to find a switchboard.    The tendrils will start growing in the form of spirals from their apical regions. The top part of the tendrils will start to move in all possible directions in order to find support. And when they find the support they stop spiraling(circumnutation).

Explanation:

The autonomic nervous system( ANS) or visceral nervous system controls the internal organ function of the human body like the heart, stomach, and lungs. The autonomic nervous system functions on its own inputs. This system contains only motor nerve fibers which will supply all the organs and glands. The autonomic nervous system may stimulate or slows down or may stop the activity of the organs depending on the situation of the input. The autonomic nervous system has two components called the sympathetic and parasympathetic nervous systems. 

The sympathetic nervous system originates from the inter mediolateral of the gray matter of our spinal cord or thoracic-lumbar region. The release of noradrenaline hormones will help the sympathetic nerve fibers to activate the organs. The parasympathetic nervous system originates from the central nervous system. It is also called craniosacral since it originates from cranial and sacral nerves. These parasympathetic nerves include the vagus nerve and cranial nerves.

Explanation:

Sweating during exercise is an involuntary action that is controlled by our autonomic nervous system. It is the reflex activity of our nervous system. Around ninety percent of our nervous activities are performed through reflexes. When we exercise our body gets warm which may cause harm to our body. In such conditions, our reflex action will help to stimulate our sweat glands as a part of thermoregulation which will result in the secretion of sweat which helps to cool down our body.

Explanation:

Switching on the night bulb reduces the secretion of melatonin hormone in our body. Melatonin is a hormone secreted by our brain as a response to darkness. It helps to maintain our circadian rhythms(our body clock) and also helps to maintain our sleep. When we are exposed to night bulbs it may result in decreased secretion of melatonin which may cause insomnia and mood changes resulting in adverse effects on our digestive system and immune system.

Explanation:

Receptors are present in our sensory organs like skin, nose, ear, tongue, and eyes. These receptors will detect the signals which are sent by our brain in the form of electrical signals. If any damage occurs to these receptors, they might not be able to detect the inputs which may put our bodies into dangerous situations.

Explanation:

Neurons are the structural and functional units of our nervous system. Neurons receive and transmit signals to various parts of our body. There are different type of neurons that transmits the information. The sensory neurons will carry the information from the sensory receptors that are present in our eyes, ears, nose, tongue, and skin to the brain. The motor neurons will transmit the information from our brain to the muscles. The interneurons will transmit the information between different neurons in the body.

The neurons may vary in shape and size depending on their location and function but all the neurons have three important parts, they are axons, cell body, and dendrites. 

Axons: These are tube-like structures that carry electrical impulses from the cell body to terminals of the axon which will pass the impulse to another neuron.

Cell body: They contain genetic information as they have a nucleus. They also have mitochondria, Golgi apparatus, and endoplasmic reticulum which will help neurons to build new axons and dendrites.

Dendrites: They receive the signals from other various neurons and carry those signals to the cell body.

Synapse: It's a chemical junction between the terminal end of one neuron and the dendrite of another neuron.

Explanation:

The chemical coordination that takes place in plants with the help of phytohormones or plant hormones which are secreted by the plants. These are the organic substances that will either promote or inhibit the growth of the plant. The plant hormones are auxins, gibberellins, cytokinins, ethylene, and abscisic acid.

1. The auxins will promote the growth of the cell, and differentiation, especially on the tip of the plant.

2. Cytokinins stimulate the cell division and lateral growth of the plant and also help in the rapid division of seeds and fruits.

3. Gibberlines help in breaking the dormancy of seeds and buds.

4. Abscisic acid act as a growth inhibitor and promotes wilting and falling of leaves

5. Ethylene promotes transverse growth and also the fruit ripening process.

Explanation:

There are multiple organs and organ systems present in a complex organism. A lack of coordination between these systems may result in mismanagement. In this, coordination refers to the regulation of the body's activity. In plants, the control system is very little because growth and reproduction are the only things that are regulated. In animals, the nervous system and endocrine system are responsible for control and coordination. The endocrine secretions regulate the proper growth and development and functioning of different organs.

Explanation:

Medulla oblongata a part of the brain controls involuntary actions. These actions are a set of muscular movements that are not under our control., such as the beating of the heart.

Reflex actions are fast and spontaneous actions as a response to a stimulus. The reflex action may involve any muscles or glands, like when we touch a hot object we immediately withdraw our hands, but involuntary actions are smooth and they do not need any kind of stimulus to work. Involuntary actions do not involve skeletal muscles whereas reflex actions involve skeletal muscles. Involuntary actions are performed throughout one's life, whereas reflex actions are produced only in emergency conditions.