ACS students' comments:
- I am beginning to understand how the brain works, and it is opening up a whole new dimension! Its fantastic. Yvonne Munshi, South Africa, Bio Psychology course.
- "A lot of the subject matter relates directly to my area of work, so it is helping me to understand it a lot more! I enjoy working in my own time and being able to take my time." Biopsychology student
How Can our Biology Affect how we Think?
Psychology can be affected by a wide range of biological factors; for example:
Stimuli to sensory organs
Electrical stimulation or lesions to parts of the cortex can affect their motor and sensory abilities. This has been confirmed when humans have had accidental damage to the brain. This work has shown that we can map the motor and sensory functions of the brain, as shown in the diagram. If a particular area of the brain shown is electrically stimulated, it will mimic the function, whilst damage will impair function. Our more complex sensory abilities have specialised areas of the brain. This is because visual and auditory processes are far more sophisticated than the sense of touch or taste. Stimulation of these areas will result in visual sensations e.g. flashes of light or auditory sensation such as a buzzing noise.
The somatosensory cortex contains our general body senses – dealing with touch, heat, cold, pressure and some aspects of pain. Stimulation here gives the sensation of touch or pressure on the skin.
Dysfunction of Sensory Organs
Damage to the brain and sensory organs can cause them to dysfunction. Damage to the eyes, optic nerves, primary visual cortex can cause loss of vision in particular portions of the visual field of complete blindness. The effect of lesions of the visual association cortex or its connections with the rest of the brain can tell us much about perceptual analysis.
Secretions of Glands
Glands are mostly controlled by the brain. Glands receive direct neural control or are controlled by events initiated by the hormones released in the hypothalamus.
Exocrine glands literally means “outside-secreting”. This includes things such as tears, secretion of digestive juices into the intestines, secretion of fluids into male genitourinary system, sweat glands secrete sweat, salivary glands produce thin watery saliva to add swallowing food. The sympathetic system causes secretion of thick, viscous saliva which explains why the inside of our mouth feels sticky when frightened or excited.
Endocrine means literally “inside secreting”. These have the effects shown in the table below. The endocrine system will be discussed in more detail in lesson 4, but basically the table below shows the major endocrine glands.