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Brain Structures & Their Function

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Presentation on theme: "Brain Structures & Their Function"— Presentation transcript:

1 Brain Structures & Their Function

2 Why should want to better understand how the brain works?
If you could learn one thing relative to the brain what would it be?

3 Overview Lobes of the brain (Forebrain) Sulci & Gyri Motor cortex
Somatosensory cortex Broca’s Area Wernicke’s Area

4 The Brain Most complex organ of the body Only weighs 1,300 grams
Contains billions of neural networks that interact to create human behaviour The brain or the encephalon is possibly the most complex organ to examine within the human body Although only weighing approximately 1,300g in the average adult, all behaviours, actions, thoughts and feelings originate from billions of neural networks interacting to create what we recognise as human. Without the brain our bodies simply would not function, making it important to have an understanding of its structure and function and the implications of diagnosis and pharmacology associated with mental illness. When looking at the brain, what is distinctive is the numerous folds that give it its wrinkled appearance. This folding together of brain tissue allows for greater amount of cerebral surface area (approx. two thirds of cerebral surface area is locate in the depths of these folds) to be confined within the limited space of the skull, leading to more information being relayed throughout areas of the brain The grooves are called fissures (extend deep into the brain) or sulci (if they are shallower) and the bumps that we see are called Gyri, and serve as markers to identify regions of the brain.

5 Cerebrum Cerebral cortex
Largest part of the brain, fills the entire upper portion of the cranium Left and Right Hemispheres The cortex (the outer layer of the cerebrum) consists of 80% of the entire brain. The cerebrum is the largest part of the brain and fills the entire upper portion of the cranium. It consists of the 2 cerebral hemispheres and sits atop of, and surrounds the brainstem leading to the spinal cord. Typically for most people the left hemisphere is dominant

6 Frontal Lobe decision making
Motor Cortex Anterior portion of the cerebrum Primary motor cortex Broca’s Area- Motor Production of speech (4:40) Personality, judgement, insight, reasoning, problem solving, abstract thinking and working memory Broca’s Area Play first 2:42 of video then skip to 4:40 Located in the front of both cerebral hemispheres, the frontal lobes are the largest lobes of the brain. Precise areas of the primary motor cortex represent particular areas of the body for example: the middle area of the cortex controls the legs, the lateral area is for the muscles of the face and largest area represented is for the arm and hands (located between both these areas). The frontal lobes are also thought to be involved in complex functioning on the brain including personality, judgment, insight, reasoning, problem solving, abstract thinking and self evaluation termed executive functions. The frontal lobe also has a function in working memory especially the ability to plan and initiate activity. Broca’s area is involved in the motor production of speech. Damage to this area produces expressive aphasia (difficulty producing the motor movements of speech)

7 Parietal lobe senses Posterior to the frontal lobe
Somatosensory cortex Wernicke’s area Posterior to the frontal lobe Somatosensory cortex Helps integrate the senses – taste, smell, auditory & visual Wernicke’s Area – understanding the spoken word The brain must always know where each part of the body is located and its relation to it’s surroundings. The anterior part (front) is responsible for receiving incoming sensory stimuli. The posterior part (rear) is continuously analyzing to give a person a sense of spatial awareness. somato-sensory cortex ( which receives general sensory information and initial reception of tactile (touch, pain, temperature) and proprioceptive( sense of position) information. The other main role of the parietal lobes are complex aspects of spatial orientation and perception, and the comprehension of language function and the ability to recognise objects by touch, calculate, write, recognise fingers of opposite hands and organise spatial directions. The posterior areas of the parietal lobes (through the dorsal stream of the visual cortex) appear to link visual and somatosensory information together. Wernicke’s Area is critical for speech including reading. It allows us to comprehend or interpret speech and to words together correctly so they make sense.

8 Occipital lobe seeing Most posterior portion of the brain
Visual processing area Stop video at 1:55 The primary visual cortex, which receives raw sensory information from the retina processes information on colour, objects and facial recognition and is also involved in the perceiving motion. Damage to the visual cortex causes cortical blindness (all structures to see are intact but the person cannot receive the input from the sensors).

9 Temporal Lobes hearing
Located at each side of the brain Receives & processing auditory information Perception of movement Recognition of faces Subdivisions cope with hearing, language, and some aspects to memory. involved in receiving and processing auditory information, higher order visual information, complex aspects of memory, language and comprehension of language, abstract thought and judgement and control of written and verbal language skills

10 Overview Two Hemispheres Corpus Colosseum Diencephalon Limbic System
Thalamus Hypothalamus Limbic System Amygdala Hippocampus

11 Hemispheres Two sides or hemispheres of the brain: LEFT & RIGHT
Connected by the corpus callosum. Each side of the brain processes things differently. Corpus callosum is a bundle of nerves that allows each side of the brain to communicate with each other.

12 Left Brain vs Right Brain
The verbal side Logical Sequential Rational Analytical Objective Looks at parts Recognizes positive emotions Right Brain The sensory side Random Intuitive Emotional Synthesizing Subjective Looks at wholes Recognizes negative emotions Left Brain recognizes letter, numbers and words Processes rapid auditory information faster than the right (crucial for separating the sounds of speech into distinct units for comprehension) is responsible for language development. It develops slower in boys, that is why males usually develop more language problems than females. Right Brain recognizes faces, places and objects The “non-verbal” side Responds to touch and music (sensory) High level mathematicians, problem solvers, and chess players use

13 What is your dominate hemisphere?
It is an outdated assumption that “artsy” type people are right-brained.

14 Diencephalon Thalamus - the sensory relay station
Transfers impulses to the correct part of the cortex for interpretation Hypothalamus -autonomic nervous system center Regulates body temperature, Controls water balance, Thirst, Hunger, etc All sensory pathways pass through the thalamus and are relayed to various areas throughout the brain. The thalamus accomplishes this by filtering incoming information and deciding what to pass on or not to pass on to cortex, preventing the overload of sensory information. The thalamus plays a role in mood and body movement associated with strong emotive responses such as fear or rage. It has some influence in prefrontal functions such as foresight and affect therefore its dysfunction has been implicated in abnormal behaviour. Hypothalamus controls the autonomic nervous system and the endocrine system. It plays a role in motivated behavior such as feeding, mating, fighting An important part of the limbic system (emotions) The pituitary gland is attached to the hypothalamus

15 The Limbic system Amygdala mediates and controls major affective mood states such as friendship, love, affection, fear, rage and aggression. Hippocampus- Memory, particularly the ability to turn short term memory into long term memory. The limbic system is the ‘emotional centre’ of the brain. Components of the limbic system help to regulate our emotions, expression of emotion and ability to learn and control impulses. The amygdala is an almond shaped structure located deep in the temporal lobe, connected to other parts of limbic system including the hippocampus and thalamus. Studies of damage to this part of the brain in animals has a taming effect (deprivation of emotion, indifference), however stimulation elicits violent aggression. The Hippocampus is a part of the limbic system, and is located deep in the temporal lobe. The Hippocampus contains a large quantity of neurotransmitters and its main functions appears to be memory - particularly turning short term memory into long term memory.

16 Overview Endocrine Glands Cerebellum Brain Stem Pituitary Pineal
Midbrain Pons Medulla Oblongata

17 Endocrine Glands Thalamus Hypothalamus
Two glands that are found in the brain are the pituitary gland hanging from the hypothalamus and the pineal gland found posterior to the thalamus. Pituitary gland “master gland” links the endocrine and nervous systems. Regulates many of the other glands. Pineal gland “third eye” melatonin to regulate sleep wake cycles. Hypothalamus

18 Cerebellum Regulates balance, muscle tone, posture, and coordination of voluntary muscle movement. Stores learned muscle movements like walking or riding a bike. The cerebellum or ‘little brain’ is located posterior to the brain stem and plays and important role in sensory perception and fine motor control. The cerebellum has two main functions; 1) Receive input from all sensory sites and project this information to other parts of the brain such as the brainstem and thalamus. 2) Act as part of the motor system regulating equilibrium, muscle tone, postural control, and coordination of voluntary movement. cerebellum is the part of the brain which allows for fine movement. Damage to the area results in poor coordination, poor motor learning, and a loss of equilibrium The pons is the main relay station between the cerebrum and the cerebellum. The majority of the brain’s noradrenaline is produced in the locus cerculeus located within the pons and aids in regulating arousal and respiration.

19 The Brainstem ( (Pathway to the Body)
Midbrain Pons Medulla oblongata At the base of brain, attaches to spinal cord Pons is the relay station between the cerebrum and the cerebellum Medulla regulates autonomic responses such as heart rate, swallowing, vomiting, coughing, sneezing The brainstem controls unconscious work such as breathing, heartbeat, and blood pressure. This area of the brain holds the key to life itself. The medulla acts as a conduction pathway for ascending and descending nerve tracks for the conscious control of skeletal muscles, balance, co-ordination, regulating sound impulses in the inner ear, regulating autonomic responses such as heart rate, breathing, swallowing, vomiting, coughing and sneezing.

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