Lecture 22 - Review Flashcards
What lobe is the hippocampus and amygdala found in?
Temporal lobe
What structures make up the limbic system?
Hippocampus
Amygdala
Fornix
Mammillary bodies
Label brain on slide 1 image 1
Label image 2
What is the output structure of the amygdala?
Fornix
What is the fornix?
When the 2 hippocampi come together to output to thee mammillary bodies
What is the function of the mammillary bodies in the limbic system?
Receive output from the fornix, and projects to the thalamus or hypothalamus
What are the 2 locations that the mammillary bodies project to in the limbic system?
Thalamus
Hypothalamus
What is the function of the mammillary bodies projecting to the thalamus in the limbic system?
Memories
What is the function of the mammillary bodies projecting to the hypothalamus in the limbic system?
Stress response
How can being an alcoholic lead to memory loss?
Alcohol damages and degenerates mammillary bodies
What part of the brain is labelled on slide 3
Mammillary bodies
What part of the brain does a stressful thought originate in?
Frontal lobe
What is the pathway of the limbic system?
Frontal lobe
Amygdala
Hippocampus to fornix
Mammillary bodies
Send to hypothalamus or thalamus
Once the limbic system reaches the hypothalamus, what hormone is made by the hypothalamus and what then happens to stimulate the stress response?
Hypothalamus makes CRH
This stimualtes the. Anterior pituitary to produce ACTH
ACTH stimulates adrenal. Cortex to make cortisol
What affect does cortisol have on the body?
Elevates blood glucose
Inc Gluconeogenesis
Reduces inflammatory response in stress responses (so is immunosuppressive can lead to infections)
What is the part of the spine that is involved in the stress response?
Hypothalamospinal tract
What happens involving the hypothalamospinal tract pathway in the stress response?
Sympathetic activation from the hypothalamospinal tract leads to the adrenal medulla releasing adrenaline
What is the theory for OCDs pathology?
Overactive direct stimulatory pathway between cortex and basal ganglia so thought keeps looping into the cortex and stress pathway
What level do sympathetic neurones get activated between int he hypothalamospinal tract?
T1 - L2
What is the main function of the thalamus?
Decides whether we perceive sensation
Sends signals to sensory cortex
What does overstimulation of the thalamus lead to?
Hallucinations
What are the 3 main functions of the reticular formation?
Consciousness
Maintains muscle tone
Paralysis in REM sleep
How is the reticular formation structured in the brain?
Network of diffuse neurones in the brainstem
What is the type of loop/mechanism which the reticular formation uses to maintain consciousness?
Positive feedback back loop
Describe the loop which the reticular formation maintains consciousness:
Reticular formation sends stimulatory signals to cortex via the reticular activating. System
Cortex then stimulates the reticular reformation leading to a cycle
Cortex can also stimualte itself keeping us awake (thoughts)
What are some UMN signs?
Spinal shock (Hypotonia -> hypertonia)
Atrophy of disuse
Hyper tonia
Spasticity
Clasp knife rigidity
What is spasticity?
Hyper tonia
Hyper-reflexia
What is clasp knife rigidity?
There’s resistance until there isn’t
How does clasp knife rigidity occur?
Golgi tendon organs activate when the tendon is stretched to the point where damage may occur
How do Golgi tendon organs prevent tendon damage?
They are supplied by sensory neurones that synapse to inhibitory interneurones
