CZZ101 revision baby pt.3

• Neuromuscular junction


  The point where a motor neuron synapses with a muscle cell
• Neuromuscular junction process


  1. Influx of sodium ions in the presynaptic membrane (neuron) causes depolarisation

  2. Neurotransmitter (ACH) released via exocytosis into the synaptic cleft

  3. Neurotransmitter binds to nicotinic acetylcholine receptors

  4. Influx of sodium into the muscle

  5. Influx of calcium into the muscle

  6. Sodium influx generates an excitatory post-synaptic potential in the plasma membrane of the muscle cell

  7. Action potential travels down the plasma membrane of the muscle cell

  8. Acetylcholine in the synaptic cleft is broken down by acetylcholinesterase
• Acetylcholinesterase prevents constant contraction
• fibroblasts are found in loose and dense connective tissue
• The 4 major parts of the brain include the brain stem, the cerebrum, the cerebellum and the diencephalon
• The cerebrum is the largest portion of the brain, it is responsible for conscious thoughts, sensations, intellect, memory and complex movements, it can broken into the right and left cerebral hemispheres.
• The cerebral cortex is broken up into gyri/gyrus (projections) and sulcus (shallow folds)
• The two hemispheres interact with each other via the corpus callosum
• the cerebrum controls conscious thought processes, intellectual function, memory storage, processing, conscious and subconscious regulation of skeletal muscle contractions
• the cerebellum is the little brain under the big brain
• the cerebellum coordinates complex somatic motor patterns, and adjusts output of other somatic motor centres in the brain and spinal cord
• The cerebellum has a sheet of grey matter which is called the cerebellar cortex and is responsible for the coordination of ongoing, repetitous movements
• the midbrain contains nuclei that is involved with the processing of auditory and visual information, they also contain centres which help to maintain consciousness
• Pons connects the cerebellum to the brainstem and contains tracts of axons, relay centres and nuclei involved with somatic and visceral motor control
• The medulla oblongata connects the brain to the spinal cord, it relays sensory information to the thalamus and other parts of the brain stem, It also houses autonomic systems which regulate the bodies major systems
• the precentral gyrus is also known as the primary motor cortex, neurons in this part direct voluntary movements by controlling somatic neurons in the brainstem and spinal cord
• the postcentral gyrus is also known as the primary somatosensory cortex, neurons in this region receive sensory information, pressure, touch, pain, vibration, temperature these sensations are relayed through the thalamus
• in the limbic system, the cingulate gyrus is located above the corpus callosum.
• limbic system

  
• the basal ganglia is responsible for proof reading information and making sure that it is all correct; it also controls movements and emotions
• the hypothalamus controls most of the ANS activity including; heart activity, blood pressure, blood temperature, endocrine activity
• the brain stem exerts direct influence over some functions, motor centres in the medulla regulate heart rate and blood vessel diameter.
• the cerebral cortex and thalamus control cerebral input, memories and emotions
• Heart rate can increase when remembering something frightening (the sympathetic nervous system)
• Parkinsons disease is when patients have difficulty initiating movements, the move abnormally slowly (hypokinesia) and they may have muscle rigidity and a resting tremor. and an absence of movement (proaykinesia)
• Huntingtons and Parkinsons are disorders of extra-pyramidal
• damage to the cerebellum impairs balance, impairs posture, impairs coordination and impairs motor learing
• the cerebellum ensures the correct movement occurs, it makes sure the movement matches the outcome specified by the cortex, it modifies. motor commands to adjust and correct voluntary movement and makes sure it matches what was planed
• the cerebellum sends adjustments to the motor cortex and the basal nuclei
• we can be born with reflexes, or the may be learned
• a reflex arc is a nerve pathway involved in a flex action, sensory neurons synapse motor neurons. '
• response =perception
• signals = sensation
• there are five receptors on the tongue; sweet, salty, sour, umami, bitter
• hearing auditory receptors are specialised hair cells within the organ of the cochlea
• Myelinated type fibres cary fast pain
• myelinated slower type of C fibres, carry slow pain
• muscle spindles increase muscle contraction
• proprioceptors, specialised type of mechanoreceptors involved in reflex actions, they sense stimuli arising within the body regarding position motion and equilibrium. located in the joints and muscles
• baroreceptors detect pressure changes