The Brain

1. The Brain

2. What does the brain do? What are the parts?

3. How good is your brain at problem solving? http://education.nationalgeographic.com/education/media/mental-shortcuts/?ar_a=1

4. Objectives • Discuss how the brain is protected and supplied with blood. • Name the major parts of the brain and explain the function of each part.

5. The Brain • Contains about 100 billion neurons and 10-50 trillion neuroglia. • It has a mass of about 3lb.

6. Parts of the Brain • Brain stem (spinal cord continues off of this) • medulla oblongata • pons • midbrain

8. Diencephalon (above the brain stem) • thalamus • hypothalamus • pineal gland

9. Cerebrum • On top of the diencephalon. • The surface has a thin layer of gray matter called the cerebral cortex beneath it is the white matter.

10. Cerebellum • posterior to the brain stem

11. Cranial Meninges • Same names as the spinal meninges. • the dura mater - superficial layer • the arachnoid mater - middle layer • the pia mater - deep layer

12. Brain Blood Supply and the Blood-Brain Barrier

13. The brain requires about 20% of the body’s oxygen supply, but is only about 2% of the total body weight. • Within about 4 minutes brain neurons begin to die if deprived of oxygen.

14. Blood-brain barrier • Tightly packed cells surround the capillaries in the brain and prevent many things from moving from the blood into brain tissue.

15. Lipid-soluble substance are able to cross the BBB. Includes: • oxygen • carbon dioxide • alcohol

16. Cerebrospinal Fluid • A clear, colorless liquid that carries oxygen and glucose from the blood to the brain tissue. • Removes waste from the brain. • Helps protect the brain and spinal cord by resisting their motion within the skull and vertebral column.

17. Provides buoyancy to brain allowing the brain and spinal cord to float. Without it the brain would flatten against the bone more due to gravity.

18. Hydrocephalus • Increased CSF accumulation in the brain resulting from an interference in drainage. • In a baby this causes the head to bulge. As the pressure increases it starts to damage brain tissue.

21. https://create.kahoot.it/?_ga=1.78696029.818897933.1427366040#quiz/83b7da9b-956b-411f-b9e5-ca4d17406e56https://create.kahoot.it/?_ga=1.78696029.818897933.1427366040#quiz/83b7da9b-956b-411f-b9e5-ca4d17406e56

22. The Brain Stem • The part of the brain between the diencephalon and the spinal cord. • Has three regions • medulla oblongata • pons • midbrain

23. Medulla Oblongata • The most inferior portion of the brain. • Carries sensory and motor information between the spinal cord and brain.

24. Location of the cardiovascular center • regulates the rate and force of the heartbeat. • regulates diameter of blood vessels.

25. Location of the medullary rhythmicity area • adjusts the rhythm of breathing • Damage to this area can lead to death.

26. Pons • the “bridge” • superior to the medulla oblongata and anterior to the cerebellum. • Contains bundles of axons that connect the cerebellum to the cerebrum.

27. Midbrain • Connects the pons to the diencephalon and cerebrum. • Also, involved in several reflexes • the pupillary reflex • the accommodation reflex (changing shape of the eye lens) • the startle reflex

29. Diencephalon • includes: • thalamus • hypothalamus • pineal gland

30. Thalamus • a pair of oval masses of gray matter • They function as relay stations for sensory information going to the cerebral cortex from other parts of the nervous system. • Ex: sight

31. Hypothalamus • a small portion of the diencephalon below the thalamus • Plays a key role in homeostasis. • Controls and integrates autonomic nervous system, Ex: movement of food through the GI tract.

32. Regulation of feelings of rage, aggression, pain and pleasure. (Along with the limbic system) • Regulates eating and drinking • Monitors and controls body temperature

33. Pineal Gland • about the size of a small pea and found in the posterior, midline of the diencephalon. • secretes the hormone melatonin which promotes sleepiness.

34. Cerebellum • located posterior to the medulla and pons and inferior to the cerebrum • regulates posture and balance • helps smooth and coordinate complex motion • Ex: with eyes closed touch the tip of your nose

35. The Cerebrum

36. What are some ways that our brain makes us different than other animals?

37. The cerebral cortex is the outer rim of gray matter. • The white matter is deep to the cerebral cortex. • It is this part of the brain that allows human to speak, read, write, plan, create and know right from wrong.

38. Appearance of the Cerebrum • The wrinkled appearance of the cerebral cortex results from rapid growth of the gray matter relative to the white matter during fetal development. • gyri (gyrus) - are the folds (“hills”) • sulci (sulcus) - are shallow grooves (“valleys”) between gyri.

39. fissures - are deep grooves between gyri

40. The cerebrum is separated into two halves by the longitudinal fissure. • These are called the right and left cerebral hemispheres. • The two hemispheres are connected by a band of white matter called the corpus callosum. (axons allowing the 2 halves to communicate)

42. The story of Phineas Gage

43. Lobes of the Cerebrum • Each hemisphere has 4 lobes. Each named for the bone that covers it. • frontal, parietal, temporal, and occipital lobes • The central sulcus separates the frontal and parietal lobes.

44. Parietal lobe • Contains the primary somatosensory area • A strip of brain tissue found just posterior to the central sulcus.

45. It receives nerve impulses for: • touch • proprioception (joint and muscle position) • pain • itching • tickle • temperature (hot and cold)

47. Occipital lobe • Contains the primary visual area • receives impulses for shape, color and visual movement.

48. Temporal lobe • Contains the primary auditory area • receives impulses for hearing • Contains the primary olfactory area • receives impulses for smell

49. Contains Wernicke’s area • involved in translating words into thought.

50. Frontal lobe • Contains the primary gustatory area • receives impulses for taste