cerebellum and lymbic system

lesson 3 unit 2 week 5

pons function

• to act as a relay station for transferring info between the cerebellum and cerbral cortex

• along with center in medulla, pons also coordinates and controls breathing

cerebellums location and function

• located at posterior region, under occipital lobe, above brain stem

• responsible for coordinated movement 

• processes sensory info 

• coordinates execution of movement in body

• structure w/ largest number of neurons in brain, recieves input from somatic receptors, receptors for equilibrium, balance + motor neurons from higher centers of brain

what specific movement does the cerebellum coordinate

• contributes to accurate limb movement

• corrects ongoing movements

• modifies strength of some reflexes

• involved in learning new muscle movements 

• as well as vestibular ocular reflex (vision stability during head movement)

in order for cerebellum to assist in making accurate limb movements and in correcting ongoing movements, it must receive…

info from two diff sources: motor cortex (must recieve same info thats traveling out to the muscles being activated) and the proprioceptors (provides info on position of the limbs in space)

what does the cerebellum compare

• the actual signal from motor cortex to that received from the proprioceptors

• ensures muscle is doing what its supposed to be doing

• if movement is not what if should be, cerebellum will modify the signals from the primary motor cortex and make adjustments

how cerebellum corrects movement

• motor cortex send motor info that 1st gets thru cerebellum before reaching muscles

• cerebellum intergrates that info

• by comparing it to info it gets from proprioceptors

• adjustments are needed in this case

• thus cerebellum makes + sends the info to the muscles to move arm (purple arrow shifted left)

• feedback recieved from sensory input, such as the visual system

• gives cerebellum additional info for making those adjustments to the command initially set by motor cortex

limbic system is the..

emotional center within brain 

hypothalamus role and relation to limbic system

• one of limbic systems components

• plays role in homeostasis and hormone release

stimulation of the hypothalamus and limbic system..

• may elicit normal behaviours such as:

• eating

• drinking

• locomotion (ability to move from one place to another)

• changes in heart rate and blood pressure

• sexual behaviours

• memory

the limbic system and hypothalamus coordinate…

• a variety autonomic, hormonal and motor effects that are associated with constant maintance of internal environment and coordinating emotional behaviours

these are components of the…

limbic system

to honnold

to stand in some high, precarious place with ur back to the wall, looking straight into the abyss; to face fear

the amygdaloid body (amygdala) is part of what system and whats its role

• part of the limbic system

• plays a role in emotion response to situations: fear, anger, anxiety, pleasure

• determines how strongly memories are stored, particularly those attached to strong response like fear or anxiety

describe the corpus callosum and its function

• this structure is a dense bundle of nerve fibers that serve as pathway and connection btwn the two cerebral hemispheres

• this connection allows the brain to integrate sensory and motor info from both sides of the body

• and to coordinate whole body movements and function

pituitary gland (hypophyse) - the two sections

• primarily regulates other endocrine organs

• anterior pituitary is derived from epithelial tissue of the pharynx

• posterior pituitary derives from neural tissue of the hypothalamus 

• the two sections secrete diff hormones and have distinct anatomical differences 

what are hormones

• chemicals that cells use to communicate with each other “long distance” thru blood stream

• they send info related to growth, stress, development and homeostasis regulation from higher integration centers to effector organs (skin, muscle, etc)

hormones secreted by pituitary are involved in

• stress response

• lactation

• growth

• development

• reproduction

function of pituitary is regulated by

hypothalamus

hypothalamus location and function

• located at base of brain, anterior to brain stem,

• responsible for temp control, body water regulation, regulation of food intake, cardiovascular and circadian clock regulation and coordination of emotional behaviours and control of hormones released from pituitary

• performs these functions thru neg feedback

temp control in the body and hypothalamus role

• body has set point for temp (~37c) thats tightly controlled thru sensory info received from peripheral tissues

• when temp rises due to exercise for ex,

• regions in hypothalamus detects this change and initiates mechanisms to return temp to set point

• mechanisms incluse sweating and vasodilation in blood vessels closer to skin to promote heat loss

• which return temp to normal

what happens when we spike a fever? why does the hypothalamus not try to reduce the body temp back down to 37

• fever is diff from a workout

• during a fever, theres presence of markers of infection (bacteria and viruses)

• hypothalamus tries to maintain temp around a set point

• when we spike a fever, set point changes to a higher temp in attempt to protect the body from invading microorganisms 

• ex set point goes from 37 to 39, hypothalamus  induce mechanisms to generate and retain heat like shivering of skeletal muscles (generates heat)

• increased vasoconstriction in periphery (reduce heat loss) thats why hands and feet are cold during fever

• bc hypothalamus is trying to conserve heat

• now hypothalamus will maintain new set point until infection is no longer detected

• thats why u sweat during a fever: hypothalamus induces heat loss mechanisms like sweating and vasodilation to increase heat loss