Chapter 7: Control and Coordination Revision Notes
- Movement refers to an organism’s capacity to move certain bodily components.
- It is termed locomotion when they move from one location to another.
Introduction to control & coordination
- Organisms respond to a variety of stimuli, including light, heat, nutrients/food, and so on.
- The neurological and endocrine systems of animals govern and coordinate all of their functions.
- Hormones are chemical messengers that help the nervous system perform a variety of tasks. Endocrine glands release these hormones.
- Hormones in plants control how they move.
THE NERVOUS SYSTEM
- The nervous system’s structural and functional unit is the neuron.
- Dendrites, cyton/soma/cell body, and axon are the three primary components of a neuron.
- Other neurons provide impulses to dendrites.
- The impulse is processed by Cyton/soma.
- The impulse is transmitted by the axon to another neuron, muscles, glands, and so on.
- Myelinated or non-myelinated axons exist.
- In myelinated neurons, impulse transmission is quicker.
The Central Nervous System
- The brain and spinal cord make up the central nervous system (CNS). The following are the functions of several sections of the brain:
- The cerebrum is in charge of reasoning, logic, emotions, speech, memory, visual processing, auditory and taste stimuli identification, and so on.
- The cerebellum is in charge of controlling and coordinating bodily motions, posture, and balance.
- Pons transmits information from the hindbrain to the forebrain.
- All involuntary motions such as vomiting, sneezing, yawning, heartbeat, breathing, blood pressure, and so on are controlled by the Medulla Oblongata.
- The spinal cord, which runs through the vertebral column and regulates reflex responses, continues as the medulla oblongata.
The Peripheral Nervous System
- The peripheral nervous system is made up of nerves that originate from the brain and spinal cord (PNS).
- Humans have 12 cranial nerves and 31 spinal nerves.
Somatic nervous system
- It is a component of the PNS.
- The somatic nervous system is made up of PNS nerves that govern the body’s voluntary activities.
Autonomic nervous system
- The autonomic nervous system is made up of all of the PNS nerves that govern the body’s automatic activities.
- The sympathetic and parasympathetic nervous systems are two divisions of the autonomic nervous system.
- The sympathetic nervous system, sometimes known as the fight-or-flight response, prepares the body for strong physical activity, whereas the parasympathetic nervous system has nearly the opposite effect, relaxing the body and inhibiting or slowing numerous high-energy tasks.
- A reflex action is an automatic, involuntary response of the body to stimuli.
- During a reflex action, an electrical impulse follows this route.
- From the receptor organ to the spinal cord/brain, the impulse travels. It is processed there, and the information is then sent back to the muscle in question, which performs the action.
- The components of a reflex arc are the receptor organ, sensory/afferent neuron, interneuron, motor/efferent neuron, and effector organ.
Protection of CNS
Three primary layers protect the brain:
- The brittle skull (cranium)
- The cerebrospinal fluid is a fluid that surrounds the brain and spinal cord.
- The meninges are the membranes that surround the brain and spinal cord (Dura mater, Arachnoid and Pia mater).
CONTROL AND COORDINATION IN PLANTS
- Plant hormones are chemicals that aid in the coordination of growth, development, and environmental reactions in plants.
Plant hormones are classified as follows: The most important plant hormones are
Auxin: Auxin is a substance that is found in (Synthesized at shoot tip).
Function: Assists in the development of the organism.
Phototropism refers to the tendency of cells to grow towards the direction of light.
Gibberellin is a hormone that aids in the development of the stem.
Cytokinins are a kind of protein that promotes cell division.
Abscisic acid inhibits growth and causes leaf withering. (The hormone that causes stress)
- Plants, unlike mammals, lack a nervous system.
- Chemicals are used by plants to regulate and coordinate their activities.
- Plant hormones are responsible for a wide range of plant motions.
Tropic Movements: Tropic movements are those that are in a certain direction in reference to the stimuli. Tropic movements occur as a result of a plant part’s development in a certain direction.
Tropic motions can be divided into four categories.
(i) Geotropic movement: Geotropic movement refers to the development of a plant component in reaction to gravity. Roots often travel in a positive geotropic direction, meaning they grow in the direction of gravity. Negative geotropic movement is common in stems.
(ii) Phototropic Movement: Phototropic movement is the development of a plant component in reaction to light. Positive phototropic movement is common in stems, while negative phototropic movement is common in roots. If a plant is kept in a container that receives no sunlight but has a hole in it that allows some light in, the stem will eventually grow towards the direction of the light. This is due to a greater rate of cell division in the section of the stem that is not exposed to sunlight. The stem bends towards the light as a consequence. Increased release of the plant hormone auxin in which it is not exposed to sunlight results in a faster rate of cell division.
(iii) Hydrotropic Movement: When roots develop in the soil, they tend to grow toward the nearest water source. This indicates that there is a positive hydrotropic movement.
(iv) Thigmotropism Movement: Thigmotropism movement is the development of a plant component in reaction to contact. Climbers’ tendrils show similar actions. The tendon develops in such a way that it may wrap around a support. The activity of auxin causes a difference in the rate of cell division in various areas of the tendon.
- Several endocrine glands make up the endocrine system.
- Endocrine glands are ductless glands.
- The product of the endocrine gland is immediately injected into the circulation.
- The endocrine glands are responsible for the production of hormones.
- Protein makes up the majority of hormones.
- Hormones help the neurological system govern and coordinate its functions.
- Because nervous systems do not react to every portion of the body, hormones are required to alter regulation and coordination in those areas. Furthermore, hormonal control is slower than neurological control.
- Hormones are chemical messengers that are released in minute amounts by specialised tissues known as ductless glands.
- They have an effect on target tissues or organs that are frequently far from their source. Hormones, which are chemical molecules, aid in the management and coordination of the endocrine system.
- A ductless gland that secretes hormones directly into the circulation is known as an endocrine gland.