how does the body respond to fear and anxiety?

 LIMBIC SYSTEM 

• Limbic comes from a latin word which means border ,the limbic system was given this name because its structures lie along a horseshoe shaped area of cortex. 

• It appears to be a border between cerebral cortex and subcortical structures of the diencephalon.

• Brain stem is known as oldest brain structure and cerebrum which is located in the upper part of the brain is considered to be the newest structure the limbic system lies between these structure .

• Parts of limbic system: thalamus,hypothalamus,amygdala,hippocampus.

• Thalamus is right above the brainstem ,egg shaped structure, like midbrain in the brainstem is a relay centre for visual,auditory and motor sensation,thalamus also acts as a relay centre .

• Thalamus first receives all sensory information ,processes it before it sends to higher region of the brain that deals 

 with sight,hearing,touch and taste.

• Smell is the only thing which will not get affected when thalamus gets injured as suppose if we smell a yummy dish ,aromatic substance it ,the senses goes directly into olfactory bulb .

• Hypothalamus is very small looks like a size of almond ,located below the thalamus ,it links endocrine system with nervous system through pituitary gland, regulation of all hormone is maintained by hypothalamus.
• Hypothalamus regulates body temperature,thirst,hunger,weight control,fatigue,sleep cycle,sexual activity,emotions ,blood pressure,heart rate,production of digestive juices ,balancing bodily fluids.

• Pituitary gland is also known as master gland since it influences control all other endocrine gland .
• Hippocampus is a greek word which means sea horse ,plays a role in consolidation of information from short term to long term memory,spatial processing and navigation.
• Spatial memory is form of memory responsible for the storage and retrieval of information within the brain that is needed both to plan a route to desired location and to remember where an object is located or where an event occurred.
• Amygdala is found right next to hippocampus and these two are responsible for fear responses  

• LUVER BUCY SYNDROME :

 When researches did an experiment in monkey by removing amygdala ,these monkey were not scared of snakes and human which generally monkey are afraid of ,loss of fear and anger symptom are just 1 of the signs and symptoms of the syndrome

• limbic system is prominent in fish ,amphibian ,reptile mammal 
• Primarily related to emotional part,concerned with memory 

FUNCTION: 

1) OLFACTION : 

piriform cortex and amygdaloid nucleus from olfactory centre.

2) Regulation of endocrine gland hypothalamus plays an important role

3) Autonomic function:

Heart rate ,blood pressure,water balance 

4) Food intake 

Feeding ,satiety centre present in hypothalamus 

5) Circadian rhythm :

 hypothalamus major role in circadian fluctuation of various physiological activity

6) Sexual  function 

Hypothalamus responsible for sexual function in both men and animal

7) Emotional state 

Maintained by hippocampus along with hypothalamus 

8)Memory ; hippocampus and pepex circuit play an important role

9) Motivation: 

Reward and punishment centre present in hypothalamus.

Papez circuit:

Papez circuit is a looped circuit in the limbic system.

 hippocampus to fornix to mammillary body ,the fibre travel in mammillothalamic tract  to anterior nucleus thalamus via thalamocortical fibre  project to cingulate gyrus and back to hippocampus through cortico hippocampal fibre and completes the circuit.

General talk: 

When we hear ,taste,smell or touch ,the thalamus  receives the sensory information,process it and sends to neocortex -known as thinking brain and amygdala which is emotional brain and responds to the situation,now imagine when you are stuck all alone in a jungle and you see a wild animal right in front of you at that time thalamus sends information to both neocortex and amygdala at the same time ,immediately amygdala initiate within seconds a fight,flight,freeze response then amygdala sends information to hypothalamus ,to pituitary to start secreting hormones from brain to blood stream to adrenal glands: secrete 2 types of hormones epinephrine( adrenaline) and cortisol and help to deal with the threat this is how all the 4 components function as limbic system hope you all got enlightened about limbic system if this post helped you do type in below at comment section .

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