NCERT Solution for Class 10 Science Chapter 7
Control and Coordination
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Intext Questions
Page No-125
Questions No-3
How does our body respond when adrenaline is secreted into the blood?
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Adrenaline is secreted directly into the blood and carried to different parts of the body. The target organs or the specific tissues on which it acts include the heart. As a result, the heart beats faster, resulting in supply of more oxygen to our muscles. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs. This diverts the blood to our skeletal muscles. The breathing rate also increases because of the contractions of the diaphragm and the rib muscles. All these responses together enable the animal body to be ready to deal with the situation. Such animal hormones are part of the endocrine system which constitutes a second way of control and coordination in our body.
Adrenalin is a hormone secreted by the adrenal glands in case of any danger or emergency or any kinds of stress. It is secreted directly into the blood and is transported to different parts of the body.
When secreted in large amounts, it speeds up the heartbeat and hence supplies more oxygen to the muscles. The breathing rate also increases due to contractions of diaphragm and rib muscles. It also increases the blood pressure. All these responses enable the body to deal with any stress or emergency.
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The heart beat increases when adrenaline is secreted into the blood so that more oxygen is supplied to our muscles. The blood supply to the digestive system and skin decreases because the small arteries around the muscles of these organs contract. This turns the direction of blood towards our skeletal muscles. The breathing rate also increases due to the contractions of the diaphragm and rib muscles. All these responses enable us to face the situations of fear and anger.
Adrenaline is also known as ‘fight or flight’ hormone. It prepares the body for emergency situations. Increased secretion of adrenaline in the blood increases the blood supply to limbs and to the facial area. It increases the heart rate and breathing rate so that more oxygen could be supplied to the limbs. Slight precipitation also occurs on the temple and in palms. All of this shows readiness for a fight or; if need be; a flight from the scene.
Adrenaline is secreted into the blood stream by adrenal gland in response to cold, joy, anger, fear and emotional stress. The hormone increases the blood supply to heart and skeletal muscles. The small arteries around digestive system and skin constrict thus diverting the blood to our muscles. The breathing rate also increases because of the contractions of diaphragm and the rib muscles. All these responses together enable our body to deal with an emergency situation.
When adrenaline, also known as epinephrine, is secreted into the blood, it triggers the “fight or flight” response. This physiological response prepares the body to react quickly to a perceived threat or stressor. Adrenaline is released by the adrenal glands, which are located on top of each kidney.
1. Increased Heart Rate: Adrenaline acts on the heart, causing it to beat faster and pump more blood. This increases blood flow to the muscles and vital organs, supplying them with oxygen and nutrients to support increased activity.
2. Dilation of Airways: Adrenaline relaxes the smooth muscles in the airways, leading to bronchodilation. This allows more air to flow in and out of the lungs, enhancing oxygen exchange. It is a beneficial response in situations where increased oxygen supply is needed for physical activity.
3. Dilation of Pupils: Adrenaline causes the pupils of the eyes to dilate (enlarge). This allows more light to enter the eyes, improving vision and making it easier to focus on the surroundings.
4. Increased Blood Flow to Muscles: Adrenaline redirects blood flow from less critical functions, such as digestion, to the muscles. This provides the muscles with more oxygen and glucose, optimizing their function for a quick and powerful physical response.
5. Release of Glucose: Adrenaline stimulates the release of glucose from the liver into the bloodstream. This provides an immediate energy source for the body, ensuring that there is enough fuel available for the increased activity during the “fight or flight” response.
6. Inhibition of Digestive Processes: Adrenaline inhibits digestive processes, such as peristalsis in the intestines and the secretion of digestive enzymes. This is because the body prioritizes resources for immediate, life-preserving activities over long-term processes like digestion.
7. Increased Blood Pressure: Adrenaline constricts blood vessels in certain areas of the body, such as the skin and digestive organs, while dilating blood vessels in the muscles and the heart. This helps to increase blood pressure and ensures that oxygen and nutrients are delivered where they are needed most.
8. Enhanced Mental Alertness: Adrenaline also has effects on the central nervous system, leading to increased mental alertness and improved focus. This heightened state of awareness is beneficial for responding quickly to a threat.
9. Sweating: Adrenaline stimulates sweat gland activity, leading to increased perspiration. Sweating helps cool the body during periods of increased physical activity.
These responses collectively prepare the body to respond effectively to a stressful or threatening situation, whether it involves physical exertion or a rapid decision-making process. Once the perceived threat is over, the body returns to its normal state through regulatory mechanisms and feedback systems.