Biology
Humans, like all living organisms, can respond to changes in the environment and so increase survival. Humans have 2 control systems to do this: the nervous system and the endocrine (hormonal) system. The human nervous system controls everything from breathing and standing upright, to memory and intelligence. It has 3 parts: detecting stimuli, coordinating and effecting a response.
Stimuli are changes in the external or internal environment, such as light waves, pressure or blood sugar. Humans can detect at least nine external stimuli and dozens of internal stimuli, so the commonly-held believe that humans have just five senses is obviously very wide of the mark!
Receptor cells detect stimuli. Receptor cells are often part of sense organs, such as the ear, eye or skin. Receptor cells all have special receptor proteins on their cell membranes that actually do the sensing, so ?receptor? can confusingly mean a protein, a cell or a group of cells.
The coordinator is the name given to the network of interneurones connecting the sensory and motor systems. It can be as simple as a single interneurone in a reflex arc, or as complicated as the human brain. Its job is to receive impulses from sensory neurones and transmit impulses to motor neurones.
Effectors are the cells that effect a response. In humans there are just two kinds: muscles and glands. Muscles include skeletal muscles, smooth muscles and cardiac muscle, and they cause all movements in humans, such as walking, talking, breathing, swallowing, peristalsis, vasodilation and giving birth. Glands can be exocrine ? secreting liquids to the outside (such as tears, sweat, mucus, enzymes or milk); or endocrine ? secreting hormones into the bloodstream.
Responses aid survival. They include movement of all kinds, secretions from glands and all behaviours such as stalking prey, communicating and reproducing.
Coordination
In multicellular organisms, such as plants and animals, it is essential that cells can communicate with each other. This allows them to coordinate their activities appropriately. Organisms have specialised cells or molecules, called receptors, which are sensitive to changes in their internal or external environment. These trigger events in the organism that bring about coordinated responses to the environmental changes.
1) Nervous and endocrine systems as communication systems
a. The basic similarities of 2 systems:
- Provide the body with methods to communicate with its internal and external environments in order to coordinate responses.
- Employ chemicals to transmit messages and respond to stimulus caused by changes in their environments.
b. The differences in response times and how they work.
- The nervous system responds to stimuli by sending electrical action potentials along neurons, which in turn transmit these action potentials to their target cells using neurotransmitters, the chemical messenger of the nervous system. This response to stimuli is near instantaneous.
- Hormones are synthesized at a distance from their target cells, and travel through the bloodstream or intercellular fluid until they reach these cells. Upon reaching their target cell, the hormones act on the cell to increase or decrease the expression of specific genes. This process takes significantly longer, as hormones must first be synthesized, transported to their target cell, and enter or signal the cell. Then, the target cell must go through the process of transcription, translation, and protein synthesis before the intended action of the hormone is seen. Although hormones act more slowly than a nervous impulse, their effects are long lasting. Additionally, target cells can respond to minute quantities of hormones and are sensitive to subtle changes in hormone concentration.
c. The nervous and endocrine systems work together to maintain homeostasis.
The endocrine and nervous systems work independently to carry out unique functions by different methods with some similar elements. However, they do work together to control and co-ordinate the internal environment of the animal.
The nervous system responds rapidly to short-term changes by sending electrical impulses.
The endocrine system brings about longer-term adaptations by sending out chemical messengers (hormones) into the bloodstream.
2) Nerve cells/Neurones
The nervous system composed of nerve cells, or neurones. A neurone has a cell body with extensions leading off it. Several dendrons carry nerve impulses towards the cell body, while a single long axon carries the nerve impulse away from the cell body. Axons and dendrons are only 10
- Human Body Systems
Human Body Systems!Integumentary System: Your body is very prone to damage, and that's why we have this system! This is an organ system that helps protect the body. It has many functions such as to cushion, excrete wastes, regulate temperatures...
- #112 Osmoregulation
Osmoregulation is the control of the water content of body fluids. It is part of homeostasis, the maintenance of a constant internal environment. It is important that cells are surrounded by tissue fluid of a similar water potential to their own...
- #109 Thermoregulation - The Control Of Body Temperature
One of the most important examples of homeostasis is the regulation of body temperature. It involves both coordination systems - nervous and endocrine. Not all animals can do this physiologically. Endotherms - Animals (e.g. birds and mammals)...
- #108 Homeostasis In Mammals
In the body of an animal conditions such as water concentration, temperature, and glucose concentration must be kept as constant as possible. Control systems that keep such conditions constant are examples of homeostasis; this is the maintenance of constant...
- # 107 Homeostasis Syllabus 2016
14.1 Homeostasis in mammals 14.2 Homeostasis in plants Cells function most efficiently if they are kept in near constant conditions. Cells in multicellular animals are surrounded by tissue fluid. The composition, pH...
Biology
#115 Control and co-ordination in mammals, the nervous system
Humans, like all living organisms, can respond to changes in the environment and so increase survival. Humans have 2 control systems to do this: the nervous system and the endocrine (hormonal) system. The human nervous system controls everything from breathing and standing upright, to memory and intelligence. It has 3 parts: detecting stimuli, coordinating and effecting a response.Receptor cells detect stimuli. Receptor cells are often part of sense organs, such as the ear, eye or skin. Receptor cells all have special receptor proteins on their cell membranes that actually do the sensing, so ?receptor? can confusingly mean a protein, a cell or a group of cells.
The coordinator is the name given to the network of interneurones connecting the sensory and motor systems. It can be as simple as a single interneurone in a reflex arc, or as complicated as the human brain. Its job is to receive impulses from sensory neurones and transmit impulses to motor neurones.
Effectors are the cells that effect a response. In humans there are just two kinds: muscles and glands. Muscles include skeletal muscles, smooth muscles and cardiac muscle, and they cause all movements in humans, such as walking, talking, breathing, swallowing, peristalsis, vasodilation and giving birth. Glands can be exocrine ? secreting liquids to the outside (such as tears, sweat, mucus, enzymes or milk); or endocrine ? secreting hormones into the bloodstream.
Responses aid survival. They include movement of all kinds, secretions from glands and all behaviours such as stalking prey, communicating and reproducing.
Coordination
In multicellular organisms, such as plants and animals, it is essential that cells can communicate with each other. This allows them to coordinate their activities appropriately. Organisms have specialised cells or molecules, called receptors, which are sensitive to changes in their internal or external environment. These trigger events in the organism that bring about coordinated responses to the environmental changes.
1) Nervous and endocrine systems as communication systems
a. The basic similarities of 2 systems:
- Provide the body with methods to communicate with its internal and external environments in order to coordinate responses.
- Employ chemicals to transmit messages and respond to stimulus caused by changes in their environments.
b. The differences in response times and how they work.
- The nervous system responds to stimuli by sending electrical action potentials along neurons, which in turn transmit these action potentials to their target cells using neurotransmitters, the chemical messenger of the nervous system. This response to stimuli is near instantaneous.
- Hormones are synthesized at a distance from their target cells, and travel through the bloodstream or intercellular fluid until they reach these cells. Upon reaching their target cell, the hormones act on the cell to increase or decrease the expression of specific genes. This process takes significantly longer, as hormones must first be synthesized, transported to their target cell, and enter or signal the cell. Then, the target cell must go through the process of transcription, translation, and protein synthesis before the intended action of the hormone is seen. Although hormones act more slowly than a nervous impulse, their effects are long lasting. Additionally, target cells can respond to minute quantities of hormones and are sensitive to subtle changes in hormone concentration.
c. The nervous and endocrine systems work together to maintain homeostasis.
The endocrine and nervous systems work independently to carry out unique functions by different methods with some similar elements. However, they do work together to control and co-ordinate the internal environment of the animal.
The nervous system responds rapidly to short-term changes by sending electrical impulses.
The endocrine system brings about longer-term adaptations by sending out chemical messengers (hormones) into the bloodstream.
2) Nerve cells/Neurones
The nervous system composed of nerve cells, or neurones. A neurone has a cell body with extensions leading off it. Several dendrons carry nerve impulses towards the cell body, while a single long axon carries the nerve impulse away from the cell body. Axons and dendrons are only 10
- Human Body Systems
Human Body Systems!Integumentary System: Your body is very prone to damage, and that's why we have this system! This is an organ system that helps protect the body. It has many functions such as to cushion, excrete wastes, regulate temperatures...
- #112 Osmoregulation
Osmoregulation is the control of the water content of body fluids. It is part of homeostasis, the maintenance of a constant internal environment. It is important that cells are surrounded by tissue fluid of a similar water potential to their own...
- #109 Thermoregulation - The Control Of Body Temperature
One of the most important examples of homeostasis is the regulation of body temperature. It involves both coordination systems - nervous and endocrine. Not all animals can do this physiologically. Endotherms - Animals (e.g. birds and mammals)...
- #108 Homeostasis In Mammals
In the body of an animal conditions such as water concentration, temperature, and glucose concentration must be kept as constant as possible. Control systems that keep such conditions constant are examples of homeostasis; this is the maintenance of constant...
- # 107 Homeostasis Syllabus 2016
14.1 Homeostasis in mammals 14.2 Homeostasis in plants Cells function most efficiently if they are kept in near constant conditions. Cells in multicellular animals are surrounded by tissue fluid. The composition, pH...
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