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The Neuron Pathways to the Nervous System. The Neuron before birth Approximately upon birth 90% of your cells are glia cells (in CNS) and Schwann cells.

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Presentation on theme: "The Neuron Pathways to the Nervous System. The Neuron before birth Approximately upon birth 90% of your cells are glia cells (in CNS) and Schwann cells."— Presentation transcript:

1 The Neuron Pathways to the Nervous System

2 The Neuron before birth Approximately upon birth 90% of your cells are glia cells (in CNS) and Schwann cells (in PNS) (fun fact: prenatal neurons develop at the rate of 250,000/minute!!)

3 Nerve fibers are long dendrites and axons bundled together. They are called nerves in the PNS and tracts in the CNS Nerves that lead to the brain are also known as: Nerves going from the brain are:

4 Neuron Parts: dendrites soma nucleus, nissl substance axon myelin sheath nodes of Ranvier terminal feet terminal buttons

5 Chemicals contained in the terminal buttons are called neurotransmitters, which will leave: The area between neurons is known as:

6 All-or-none law The all-or-none law states that when a neuron is stimulated, it must stimulated to:

7 Ways of Measuring the Brain Electroencephalograph -EEG- Measures: Used in sleep research, detects dreams and sleep disorders

8 Ways of Measuring the Brain Lesioning Intentional damage to brain cells: Lesioning has taught us a lot about the functions of the brain

9 Ways to Measure the Brain CT-Computerized Tomography Horizontal slices: Least expensive – widely used

10 Ways to Measure the Brain Positron Emission Tomography (PET) Radioactive tracer Color coded map

11 Ways to Measure the Brain Magnetic Resonance Imaging (MRI) What it is: Very expensive

12 Ways of Measuring the Brain Electrical Stimulation of the Brain (ESB) Sends a weak: Stimulates areas of the brain to determine what effect the stimulation has Discovered by Penfield, done:

13 Neurotransmitters

14 Acetylcholine-Ach Involved in voluntary movements Contributes to: Lack of Ach – Low levels of Ach – cells die

15 Acetylcholine Hippocampus of the brain Overabundance of Ach- Curare-a poison that blocks the transmission of Ach, which will lead to intense spasms of the muscles, including heart –

16 Dopamine-DA Controls voluntary muscles A monoamine Lack of – Too much –

17 Dopamine Tardive Dyskenesia-a disease which can cause Parkinson’s-like tremors. This occurs when a person takes meds for: Plays a major role in addiction as it is similar to adrenaline and controls:

18 Serotonin-SE Highly implicated in, hence your SSRI’s (antidepressants) Low levels of SE seemed to be linked to: Involved in wakefulness and: A Monoamine

19 Norepinephrine-NE Low levels of NE have been associated with: Cocaine and amphetamines may stimulate the activity of this neurotransmitter (may cause hallucinations) A monoamine

20 Epinephrine Synthesized by the: Activates the sympathetic nervous system and puts the body:

21 Endorphins Resemble opiates Pain blockers Gate control theory:

22 GABA Low levels: Antianxiety drugs:

23 Central and Peripheral Nervous Systems Central Nervous System – –Consists of the:

24 Peripheral Nervous System Contains: –Somatic Nervous System: –Autonomic Nervous System: Sympathetic NS

25 Peripheral Nervous System Parasympathetic –Rest and digest response –Brings the system back to:

26 The Brain Did you know that the brain weighs only about 1 pound at birth? By one year of age, the brain will double in size and be almost 90% of its adult size

27 Lobes of the Brain FRONTAL LOBE Located in front of the central sulcus. Concerned with:

28 Lobes of the Brain Frontal Lobe- On the left side is Broca’s area –

29 Motor Strip

30 Phineas Gage After Gage had an accident in which a metal pipe went through his brain, it was thought that he would not survive. However, he did – with interesting consequences

31

32 Lobes of the brain PARIETAL LOBE Located behind the central sulcus. Concerned with:

33 The Primary Somatosensory Cortex Neurons in the primary somatosensory are activated when the skin is touched. However, the body is NOT represented in the cortex in proportion to the amount of skin.

34 A map of the human somatosensory cortex was drawn by Dr. Wilder Penfield in the 1950's. By observing the location on the brain that caused patients to feel sensations on different parts of their bodies, Dr. Penfield was able to draw a map of the brain

35 Lobes of the Brain TEMPORAL LOBE Located below the lateral fissure. Concerned with:

36 Lobes of the Brain Temporal Lobe – Behind the temporal lobe is the uncus – Left side of temporal lobe is Wernicke’s area -

37 Lobes of the Brain OCCIPITAL LOBE Located at the back of the brain, behind the parietal lobe and temporal lobe. Concerned with:

38 The Lobes of the Brain.

39

40 Medial View Sensory & Motor Areas

41 The Brain Brain Weight(gm) Species 6,000 Elephant 1,300- 1,400 Adult Human 97 Rhesus Monkey 72Dog 30 Cat 10Rabbit 2.2Owl

42 How does the human brain compare?

43 Parts of the Brain Cerebral cortex functions: Thought Voluntary movement Language Reasoning Perception

44 The Hindbrain Cerebellum Functions: Looks like a mini-brain

45 Cerebellum Two peach-size mounds of folded tissue at the base of the brain form the cerebellum. Damage to this area leads to: Some scientists have discovered:

46 The Hindbrain Medulla Control of: –a.k.a. the medulla oblongata

47 The Hindbrain Pons –Located above the medulla –Connects midbrain with the: –Controls: –Contains sensory and motor tracts between the cortex and the medulla –Involved in:

48 The Midbrain The midbrain is very small in humans Coordinates simple movements with sensory information

49 The Midbrain Reticular formation (a.k.a. Reticular activating system) Attention and arousal- If damaged, the person may: Involved in pain perception

50 The Forebrain Thalamus –Functions as a relay station – sends sensory information to: –The only sensory information that does not travel through the thalamus is:

51 The Forebrain Hypothalamus Known for four F’s- Although the pituitary gland is given credit for regulating the endocrine system, it is the hypothalamus that sends the message to:

52 The Forebrain Hypothalamus –Regulates: –Controls your biological rhythms, so it is also involved with whether you are a morning person or an afternoon person

53 The Forebrain Limbic system: –Regulation of emotions- –Also known for being involved with: –Hippocampus, amygdala, septum, part of the thalamus and hypothalamus

54 The Forebrain Hippocampus Involved in memory and how we: Removal of temporal lobe can result in:

55 The Forebrain Hippocampus- Many memories are not stored there, however, the hippocampus sends information to different areas of the cerebral cortex for processing

56 The Forebrain Amygdala Plays a role in aggression and defensiveness When damaged: When stimulated:

57 The Forebrain Septum Important pleasure center of the brain – mild stimulation of this area may result in intense pleasurable feelings, including intense sexual arousal Lesions to the septal area may result in: Stimulation results in:

58 Corpus Callosum The brain has identical parts in each hemisphere The corpus callosum connects: Often cut in patients with:

59 Cerebrum Largest part of the brain –Divided into two hemispheres – each hemisphere has identical parts: –Separate by the- –Divided into four lobes

60 Hemispheres of the Brain Are you right-handed or left-handed? About 90% of the population are right-handed - they prefer to use their right hand to write, eat and throw a ball ("right hand dominant.“) Most of the other 10% of the population is left- handed or "left hand dominant." There are few people who use each hand equally; they are "ambidextrous.” Brain Hemispheres

61 Marion Diamond Demonstrated that an enriched environment will increase cell weight and add to the number of dendrites on the neuron An impoverished environment decreases cell weight:

62 Environmental impact on the brain.. From the time a baby is born (and possibly before) they are beginning the formation of trillions of neuronal connections via the environment Neurons will constantly grow, die, become stronger or weaker depending on the environment

63 Emotions and learning Positive emotions, however, can enhance learning When students laugh or have positive feelings towards learning they are more likely to learn

64 The Adolescent Brain “What were you thinking?” “Don’t you ever think before you act?” “When are you going to make better decisions?” “How many times do I have to say the same thing over and over again?” Any of this sound familiar?

65 The Adolescent Brain The prefrontal cortex has not fully developed and the thinking, judging, planning portion of their brain is not functioning to its fullest capacity

66 The Adolescent Brain New research indicates that the adolescent brain has new cell growth and new neural connections This new growth and the pruning of neurons not in use help the brain develop emotional maturity

67 Diseases of the brain Alzheimer’s Disease –have gradual memory loss and difficulty with language and emotion –while the disease starts out slowly, it progresses to the point that the person needs help eating, bathing and using the bathroom

68 Diseases of the brain Scans may help in the diagnosis –CAT scans tend to help visualize brain shrinkage and enlarged ventricles

69 Diseases of the brain Research has demonstrated that the more neuronal connections one has, the more likely they are to lessen the effects of AD Therefore, one should keep active physically and mentally


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