BIOLOGY 1 Marks Question

3. Blind spot

Solution:

Blind spot is the part where the optic nerve passes out of the retina. Photoreceptors are absent from this region.

1. Hypothalamus.
2. Medulla.

1. Synaptic knobs.
2. Schwann cell.

1. Cerebral aqueduct.
2. Corpora quadrigemina.

1. Sensory.
2. Neurons.

1. The projecting ridge having hair cells, found in the base of the semicircular canals (called ampulla), is called crista ampullaris.
2.  

1. The projecting ridge found in the utricle and saccule of the vestibular apparatus, is called macula.
2. Both are receptors to maintain the balance of the body.

1. Perilymph.
2. Organ of Corti.

1. In the sockets, called orbits.
2. Inside the spinal cord.

1. Corpus callosum.
2. Thalamus.

1. permeability of axolemma (axon membrane).
2. Osmotic equilibrium between the axoplasm and extracellular fluid present outside the axon.

1. Synaptic vesicles are present in the synaptic knob, the bulb-like structures at the ends of the branches of axon.
2. They contain neurotransmitters.

1. Hearing
2. Body balance.

• Specific receptor receive a stimulus and set up a sensory impulse.
• Afferent neuron brings sensory impulse from receptor to central nervous system.
• Intermediate neuron transfers impulse from afferent neuron to efferent neuron.
• Efferent neuron carries motor impulse from central nervous system to specific effector.
• Effector is the organ/ gland, which functions according to the impulse received.

1. Dura mater (Hard mother).
2. Arachnoid mater.
3. Pia mater (Soft mother).