The nervous system and brain Flashcards
What are the two main divisions of the nervous system?
1) Central nervous system —> brain and spinal cord
2) Peripherial Nervous system —> everything outside of brain and spinal cord
What are the 3 types of neurons and what do they do?
1) Sensory neurons: inputs messages from sensory organs to parts of the brain and spinal cord
2) Motor neurons: output messages from the brain and spinal cord to body’s muscles and organs
3) Interneurons: preform connective or associative functions within the nervous system (tells where the sensory and motor neurons have to go)
What does the peripherial nervous system consist of?
It consists of the somatic nervous system and the autonomic nervous system.
The somatic nervous system is sensory neurons transmitting messages to the brain and motor neurons responding accordingly to that message being outputted.
The autonomic nervous system:
- involves our internal environment and controls glands and smooth muscles (like our heart, blood vessels, and lining of our stomach and intenstines…) this is all involuntary
There are two parts of the autonomic system:
1) Sympathetic nervous system (activation or arousal) fight or flight
and
2) parasympathetc nervous system (slows down body processes and maintains or returns to rest)
Together the parasympathetic and sympathetic nervous systems maintain homeostasis (balance of internal state)
What is a benefit from spinal reflexes?
They reduce reaction time because instead of the stimulus going all the way up to your brain, it goes to the spinal cord which makes it faster to respond in a way so you can protect yourself
What are the 3 main portions of the brain?
the hindbrain, the midbrain and the forebrain
What are the 3 components of the hindbrain and what is the overall function of the components in the hindbrain?
the 3 component of the hindbrain are:
1) Pons: bridge that connects nerve impulses between higher and lower levels of the nervous system
2) Medulla: takes care of vital body functions like heart rate, respiration… and circulation..hunger…
3) Cerebellum: concerned with involuntary muscle movement and rhythmic coordination (like walking)
Overall, the hindbrain is involved with maintenance and regulation of body functions. Brain damage to the hindbrain can be very severe and fatal because its controlling the basic functions of our body that we cannot survive without
What is the midbrain? what 3 components is it composed of?
Midbrain controls interactions with parts of the environment
It is composed of
1) Tegementum which is involved in integration of sensory information and directs movement (freezing in one spot or reflex action in relation to an environmental stimulus)
2) Reticular formation: blocks or allows certain messages sent from the sensory input to the higher parts of the brain. Ascending reticular formation is sending input to higher regions of the brain to alert it and descending reticular formation is the higher regions of the brain either admitting or blocking out that sensory input
3) Tectum: Orientation and movement towards an enviromental stimuli (i.e. moving towards food when you’re hungry)
What is the forebrain composed out of? And what is the significance of the forebrain in mammals?
Forebrain appears to bigger in higher order mammals like humans and chimps. Its the part of the brain involved in cognitive functions like memory, language, learning … etc
Its composed of:
1)the Four Lobes (Frontal, Parietal, Occipital and Temporal)
2) The limbic system (hippocampus, amygdala, nucleus accumbens)
3) Hypothalamus
4) Thalamus
5) Fusiform Gyrus
6) Basal Ganglia
Describe the parts of the forebrain except the 4 lobes?
1) Thalamus —> involved in sensory relay station… tells which lobe sensory input should go to
2) Basal Ganglia –> involved in voluntary motor control… i.e. if you want to initiate picking up a pen to write, you use your basal ganglia for that initial picking up action
3) Hypothalamus –> regulator of biological drives such as the endocrine system (hormones), sexual behaviour, body temperature, eating, drinking, aggression and expression of emotion. Also has a direct response to the pituitary gland (where hormones get produced/released)
4) Fusiform Gyrus: Part of the brain that recognizes/ has a familiarity with upright faces
- Parts of the limbic system helps coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus
1) Hippocampus: involved in forming and retrieving memory
2) Amygdala: organizes emotional response patters (usually towards fear and aggression)
3) Nucleus accumbens: is the release site of dopamine from axon terminals to nucleus accumbens that causes a feeling of reward and motivation
What is the prefontal cortext significant for?
- Its only in higher order mammals
- Involvd in goal setting, judgement, strategic planning and impulse control
What is broca’s aphasia and where does it occur?
Broca’s aphasia occurs in the broca’s area within the frontal lobe. It is involved in formation of speech, forming sequences of fine motor movements needed to speak and involved in ability to use grammar and find the correct word
What is Wernicke’s aphasia? Where does it occur?
Wernicke’s aphasia occurs in Wernicke’s Area in the temporal lobe and is involved in understanding and comprehending speech
What results from hippocampus damage and what parts of the brain functions are intact from it?
Hippocampus damage results in the inability to form new factual and episodic memories (long term memory)
Parts of the brain function that are still intact are:
- short term memory
- General intelligence (IQ)
- procedural memory (remembers certain procedures)
What is anterograde Amnesia?
Damage to hippocampus resulting in long term memory loss
What are the Motor and Somatosensory Cortices?
They are the area between the frontal and parietal lobe.
- The motor cortex is involved in the parts of our bodies that we can move. The amount of cortex dedicated to a body part depends on the complexity of the movements that are carried out in that body part (for example: our fingers have more motor cortex area because we use them more than other body parts like the torso)
- The sensory Cortex –> receives sensory input that gives rise to our sensations of heat, touch, cold and balance + body movement.
- Its organized in an upside down fashion with our feet being near the top of our brain
Both the motor and somatosensory cortexes are cortices because they are subject to flexiability and change. If we use one part of our bodies more (for example, a musician uses his fingers more to play a guitar) then more space and area will be dedicated to his motor cortex and sensory cortex). Same way as a blind person using their fingers to read braille will develope a large sensory cortex area to their finger tips
