Review Dr. Anna L. Kiss Department of Human Morphology and Developmental Biology Semmelweis University, Budapest 2014
Eye 1.) Fibrous layer: sclera cornea 2.) Vasculose layer: choroid ciliary body iris 3.) Nervous layer: retina optic retina (10 layers) blind retina (2 layers)
Eye
Muscles of the eyeball Innervation: Oculomotory: sup.rectus inf. rectus medial rectus inf. Oblique Trochlear n: sup. oblique Abducens n: lateral rectus
Inner muscles of the eye: Iris Innervation: sympathetic and parasympathetic
Ear 1.) External ear 2.) Middle ear (tympanic cavity) 3.) Inner ear
Ear
Organ of Corti
Organ of Corti
Organ of balance
Organ of balance
Taste sensation: taste buds
Brainstem Olive Pyramid Dorsal view Ventral view
Functions of Reticular formation (RF) Perception of pain (formation,modification) Modify the reflex activity of spinal cord and brainstem) Modification of activity of limbic system (emotion, sexual behaviour) sleep-awarness balance ARAS (ascending reticular activating system)
Functions of Reticular formation (RF) Perception of pain (formation,modification) Modify the reflex activity of spinal cord and brainstem) Modification of activity of limbic system (emotion, sexual behaviour) sleep-awarness balance ARAS (ascending reticular activating system)
Afferent connections of cerebellum Spinocerebellar tracts Vestibulocerebellar tract Pontocrebellar tract mossy fibres Reticulocerebellar tract Olivocrebellar tract- climbing fibres
Efferent connections of cerebellum Cerebellovestibular tract Cerebelloreticular tract Cerebellorubral tract Cerebellothalamic tract
THALAMUS Each half of the brain contains a thalamus, a large, ovoid, gray mass of nuclei
Functional Divisions of the Thalamus Thalamus is thought to be the crucial structure for the perception of some types of sensation, especially pain, and the sensory cortex may give finer detail to the sensation. The thalamus can be divided into five functional nuclear groups: Sensory nuclei are involved in relaying and modifying sensory signals from the body, face, retina, cochlea, and taste receptors Motor nuclei convey motor information from the cerebellum to the precentral motor cortex, Limbic nuclei, convey information from the hypothalamus and the cerebral cortex. Multimodal nuclei, have connections with the association areas in the parietal lobe Intralaminar nuclei– non specific connections (not well understood) Interaction with cortical motor areas, the caudate nucleus, the putamen, and the cerebellum has been demonstrated.
Regulatory functions of the hypothalamus: Functions — its most important job is to maintain homeostasis (or maintaining the body’s status quo); it does so by regulating three interrelated functions: Neuroendocrine Function — controls hormone release by the pituitary gland. Autonomic Function — integrates autonomic functions via direct projections to preganglionic autonomic neurons located in the brain-stem and spinal cord. Emotions and Drives — it has numerous interconnections with the limbic system by which it generates behaviors involved in rage, aggression, escape, etc.
Basal ganglia caudate nucleus lentiforme nucleus claustrum substantia nigra putamen globus pallidus
Basic definitions General sensation: Special sensation: Pain Temperature Pressure, vibration Proprioception (information from joints, tendons, muscles) Special sensation: Taste
General organisation of spinal cord Pseudounipolar cell
Division of sensory information Epicritic sensation: fine touch, fine vibration-pressure, proprioception, two point discrimination B) Protophatic sensation: crude touch, crude vibration-pressure pain and temperature
Sensory pathways Epicritic sensory pathways Cuneate and gracile fasciculi: From the level of medulla the fibers cross the midline and named as medial lemniscus CONSCIOUS epicritic Dorsal(posterior) spinocerebellar tract (uncrossed) Ventral (anterior) spinocerebellar tract (crossed-at the level of spinal cord) Terminate in the cerebellar cortex as mossy fibers Both carry information about epicritic sensation but they do not reach the thalamusUNCONSIOUS tracts
Sensory pathways: protophatic pathway (anterolateral system) Ventral and lateral spinothalamic tracts (crossed) Ventral spinothalamic tract carries information about rough touch, vibration, pressure Lateral spinothalamic tract carries information about pain and temperature Both terminate in the thalamus VPl nucleus (conscius tract) and the fibers after synapse reach the primary somatosensibility area (Brodman 3,1,2 area) Anterolateral system
Summary of sensory pathways Epicritic, protopathic info via trigeminal lemniscus Head and neck Thalamus Vpm Taste info via solitary tract Sensory cortex Epicritic info via medial lemniscus Spinal cord (trunk and limbs) Thalamus Vpl Protopathic info via spinothalamic tract
Motor pathways I. Pyramidal tract =corticospinal tract Anterior corticospianltract (crosses at the level of SC) Lateral corticospinal tract (crosses at the level of medulla=pyramidal decussation) The motor axis of the body Gives the command to the skeletal muscles ‘what to do’
Innervation of skeletal muscles Alpha motor neurons innervate the skeletal muscles of trunk and limbs (neuromuscular junctions-motor end plates)
Motor pathways II. Extrapyramidal system Refine the activity of corticospinanl tract and gives the command ‘how to do’ Maintain a continous muscle tone (mainly inantigravitation muscles=extensors) Synchronize the movements of eyeball and head-neck muscles Reset the sensitivity of muscle spindle!!