Chapter 9, 10, 11 Flashcards
What is the central nervous system comrpised of?
- Composed of the brain and spinal cord
- Receives sensory information from sensory neurons
- Sends signals to muscles and glands via motor neurons
- Integrate sensory information and helps direct motor responses with association neurons
Maintain homeostasis
Respond to environment
What are sensory pathways?
What is the Brain and what is it composed of?
- Made up of 4 main regions
Cerebrum, Diencephalon, Cerebellum, Brainstem - Adult brain has 100 billion neurons
- Receives 15% of blood flow and 50% of glucose
- Oxygen freely crosses blood-brain barrier
- Not physical size of brain that determines intelligence
What is the Cerebrum?
- Largest portion of the brain (80%)
- Responsible for higher mental functions and processing sensory and motor information
- Precentral gyri control movements on opposite side body
- Postcentral gyrus receives somatosensory information from opposite side of body
- L & R Hemispheres connected by corpus callosum
- Some tasks performed better by one side of brain
- Right hemisphere: visuospacial tasks, music, maps, art
- Left hemisphere: Language, speech, writing, math
What does the Homoculus map of the Precentral and Postcentral Gyri represent?
Each body part is represented next to the area of the cortex thatprocesses information for that body part. This mapping was created in
1950 by Penfield, a neurosurgeon, and is called a homunculus (little man).
What is the Limbic system?
- Part of our ancient primitive brain
- Few synaptic connections to cerebral cortex, which is why it is hard to control your emotions
- Emotions controlled by the limbic system:
- Aggression
- Fear
- Humans
- Monkeys - Hunger/satiety
- Goal-directed behaviors
- Sex drive
What is the Thalamus and Hypothalamus?
- Thalamus is relay center through which most sensory information passes to cerebrum
Only smell does not pass
- Hypothalamus important for maintaining homeostasis and regulating the ANS
Hunger/satiety and thirst
Temperature
Sleep and wakefulness
Emotions - fear, anger, pain, and pleasure
Controls endocrine system via ant. pituitary
What is the Medulla oblangata and Pons?
- Medulla contains nuclei required for regulation of cardiovascular and breathing response = vital centers
Vasomotor center – blood vessel diameter
Cardiac control center – heart rate
Rhythmicity center – respiration
- Pons also has respiratory centers that help regulate breathing
What is the Cerebellum?
- Receives input from proprioceptors in joints, tendons, and muscles
- Nerve fibers pass through thalamus to motor cortex to coordinate movement
- Needed for motor learning, timing and coordination of movement
What are the two types of Consciousness?
Two distinct concepts:
- Refers to experiences
- Thoughts, feelings, emotions, dreams
- State of Consciousness
- Describes a spectrum of behavior
- Pattern of brain activity which can be measured with an EEG
How does learning and memory work?
- Learning has two broad types
* *Associative**
- Stimuli associated through Reinforcement & Punishment -
Nonassociative
- Habituation
- Sensitization - Memory has several types
* *Short-term working memory**
* *Long-term** that requires actual structural change
- Declarative: can be verbalized
- Nondeclarative: motor skills
Which type of memory requires synaptic changes?
- Short-term memory involves a recurrent circuit where neurons synapse on each other in a circle
- Interruption of the circuit destroys the memory – there was no structural change
- Long-term memory requires permanent change in neuron chemical structure and synapses
What are Nerves?
- Bundles of axons located in PNS
- Most contain both sensory and motor neurons so are called mixed nerves
- Bundle of axons in CNS is tract
- 31 pairs of Spinal Nerves arise directly from spinal cord
- In a spinal reflex, sensory info can be acted on at level of spinal cord
What are the Three types of Tracts in the Brain?
-
Association
Within same hemisphere -
Commissure
Between hemispheres and lobes - Projection
Transfer info up and down cord
-Ascending Tracts carry sensory information body brain
-Descending Tracts motor info brain muscles and glands
What are the Motor Divi**sions of the PNS?
-
Somatic motor neurons
Control skeletal muscles -
Autonomic neurons
-Control smooth and cardiac muscle, many glands, lymphoid and some adipose tissues
-Sympathetic branch is fight-or-flight
-Parasympathetic branch is rest-and-digest
-Works with endocrine system to maintain homeostasis
What is the Antagonistic control of the ANS?
Most internal organs are under antagonistic control
One autonomic branch is excitatory, the other branch is inhibitory
Example: Effector organ heart
Sympathetic response increases heart rate
Parasympathetic response slows rate
What is the difference between the Sympathetic vs Parasympathetic?
Most visceral organs are innervated by both sympathetic and parasympathetic neurons.
