control and coordination

• The cerebral cortex is the outer layer of gray matter that covers most of the brain's surface.
• The medulla oblongata controls involuntary functions such as breathing, heart rate, blood pressure, swallowing, vomiting, sneezing, coughing, digestion, and sleep-wake cycles.
• The hypothalamus regulates body temperature, hunger, thirst, fatigue, emotions, and sexual behavior.
• Specialised tips of nerve cells detect all information from the environment
• Receptors for taste are gustatory receptors, for smell are olfactory receptors, and for light are photoreceptors in the eye
• Acquired information triggers a chemical reaction creating an impulse
• Nerve impulse is an electrical impulse transmitted along a nerve fibre
• Impulse travels from dendrite to cell body
• At the end of the axon, impulse triggers the release of chemicals
• Chemicals travel across synapse where two nerve cells meet
• Reflex arcs involve the detection of input by sense organs and a response by an output action
• Signals are transmitted from a receptor to a muscle or gland through a reflex arc
• Reflex arcs are formed in the spinal cord, but information also reaches the brain
• Sequence of reflex arc: Receptor → Sensory neuron → Spinal cord → Motor neuron → Muscle
• The brain is the main coordinating center of the body
• Central Nervous System (CNS) consists of the brain and spinal cord
• Peripheral Nervous System (PNS) facilitates communication between the CNS and other parts of the body
• Parts of the brain: Forebrain, Hindbrain (Medulla, Cerebellum, Pons)
• Neuron is the structural and functional unit of the human nervous system
• Plants detect touch through movements that happen at a different place from the point of touch
• Plants use electrical and chemical means to convey information
• Tendrils in plants are sensitive to touch and help in climbing
• Tropic movements in plants are directional growth movements in response to external stimuli
• Shoots are positively phototropic (bend towards light), roots are negatively phototropic (bend away from light)
• Pollen tubes grow towards ovules (chemotropic)
• Phytohormones regulate growth, development, and cell division in plants (Auxins, Gibberellins, Cytokinins, ABA)
• Endocrine system includes hormones like Thyroxin, Growth hormone, Testosterone, Oestrogen, Insulin, Adrenaline
• Thyroxin regulates metabolism for body growth, Growth hormone stimulates growth in all organs
• Testosterone is for the development of male sex organs, Oestrogen for female sex organs and menstrual cycle regulation
• Insulin regulates blood sugar level, Adrenaline readies the body for danger situations
• Chemotropism is the directional growth of plants in response to chemical stimulus
• Glucagon is released from the pancreas to convert glycogen into glucose
• Consequences of haemoglobin shortage include anemia and reduced oxygen transport capacity
• Spinal cord is protected by the vertebral column
• Insufficient insulin causes diabetes
• Nervous and endocrine systems control and regulate life processes
• Cerebrum is responsible for sensory processing, Hypothalamus controls sleep and wake cycle
• Nervous and hormonal systems together perform control and coordination in the body
• Blinking of eyes is a reflex action, Pituitary gland is unpaired
• Neuron structure:

  • Cell body (cyton): Contains a central nucleus, cytoplasm, etc.
  • Dendrites: Branched processes of the cell body that receive and transmit stimulus
  • Axon: Conducts impulses away from the cell body, covered with a myelin sheath
  • Nerve ending: Fine branches that transmit electrical impulses to another neuron