biol 2410 - unit 6

What is sensory physiology?

The study of how the nervous system gathers information about the internal and external environment to maintain homeostasis.

How many senses do humans have?

Humans have between 9 to 21 senses, more than the traditional five.

What are conscious senses?

Senses that are perceived and processed in the conscious areas of the brain, which include somatic senses and special senses.

What are somatic senses?

Senses such as touch, temperature, pain, itch, and proprioception (position of the body).

What are special senses?

Senses such as vision, hearing, taste (gustation), smell (olfaction), and balance (equilibrium).

What are unconscious senses?

Senses processed in areas of the brain outside of the cerebral cortex, including somatic and visceral stimuli.

What do somatic stimuli include?

Muscle length and tension, and proprioception.

What do visceral stimuli monitor?

Blood pressure, blood glucose concentration, core body temperature, and other internal conditions.

What is a sensory receptor's threshold?

The minimum stimulus required to activate a receptor.

What is signal transduction?

The process by which sensory receptors convert a stimulus into graded potentials.

What are tonic receptors?

Slowly adapting receptors that maintain their firing rate under a constant stimulus.

What are phasic receptors?

Rapidly adapting receptors that fire at the onset of a stimulus and stop if the stimulus intensity remains constant.

What are the two main types of pain?

Fast pain, transmitted rapidly through Aδ fibers, and slow pain, transmitted slowly through C fibers.

What is the role of the thalamus in sensory pathways?

It relays sensory signals to the appropriate area of the cortex.

What is lateral inhibition?

A mechanism to increase contrast between activated receptive fields and non-activated fields, helping to localize stimuli.

Describe the function of nociceptors.

Nociceptors detect pain and are activated by noxious stimuli that may damage tissues.

How does the sensory pathway for hearing begin?

It starts with primary auditory neurons that form the cochlear branch of Cranial Nerve VIII.

What is the function of olfactory receptors?

They detect odorant molecules and are involved in the process of olfaction (smell).

What are the components of the ear involved in hearing?

The outer ear, middle ear ossicles, and inner ear, which includes the cochlea.

What are the five taste sensations involved in gustation?

Sweet, bitter, umami, sour, and salt.

What does the somatosensory cortex perceive?

It perceives general senses such as touch, temperature, and pain.

What is sensory acuity?

How accurately a stimulus can be located based on receptive field size and convergence.

Define the term 'receptive field'.

The physical area in which the presence of a stimulus will activate a receptor.

What is the difference between sensation and perception?

Sensation is the detection of sensory information, while perception is the interpretation and awareness of that information.

What is the role of photoreceptors in vision?

They transduce light energy into electrical signals for vision.

What is anosmia?

The loss of the sense of smell, often associated with COVID-19.

What is the primary function of thermoreceptors?

To detect changes in temperature.

What is the function of mechanoreceptors?

To detect physical forces such as touch, pressure, and vibrations.

What is the function of hair cells in the cochlea?

They are mechanoreceptor cells that transduce sound vibrations into electrical signals.

What is the visual pathway for processing visual information?

Signals travel from photoreceptors to bipolar cells, then to ganglion cells, forming the optic nerve, which relays signals to the brain.

What adaptations occur in the presence of continuous stimuli?

Some receptors decrease action potential frequency, which is known as adaptation.

What causes conductive hearing loss?

Blockages or damage preventing sound transmission through the middle ear.