1 Development,Aging & Disorders Homeostatic Imbalances and Disorders Ronald Aguilera and Ryan Roman

2 General Development of Brain During 3rd wk. of gestation, ectoderm thickens into Neural Plate. Neural groove (longitudinal) and Neural folds (raised edges) are formed Folds meet to form Neural Tube Inside the neural tube is the Neural Crest, a mass of tissue adjacent to neural tube Neural Crest eventually forms: ◦Spinal and Cranial Nerves ◦Ganglia of Cranial Nerves ◦And much more 2

3 General Development of Brain 3 layers of cells differentiate from walls of neural tube: ◦(Outer) Marginal Layer cells become white matter ◦(Middle) Mantle Layer cells become gray mater ◦(Inner) Ependymal Layer cells become lining of central canal of spinal cord and ventricles of brain 3

4 General Development of Brain During 3rd to 4th wk. of embryonic development, neural tube develops into three Primary Brain Vesicles: ◦Prosencephalon (Forebrain) ◦Mesencephalon (Midbrain) ◦Rhombencephalon (Hindbrain) During 5th wk. of development, Secondary Brain Vesicles develop ◦Prosencephalon -> Telencephalon & Diencephalon ◦Rhombencephalon -> Metencephalon & Myelencephalon  Area of neural tube inferior to myelencephalon becomes the Spinal Cord 4

5 General Development of Brain Telecephalon -> cerebral hemispheres (basal ganglia, lateral ventricles) Diencephalon -> thalamus, hypothalamus, epithalamus Mesencephalon -> midbrain, cerebral aqueduct Metencephalon -> pons, cerebellum, and houses part of the 4th ventricle Myelencephalon -> medulla oblongata, and houses the remainder of 4th ventricle 5

6 Aging and the Nervous System The older we get, the more the Nervous System gets weaker ◦# of synaptic contacts declines ◦Decrease in brain mass and nerve cells ◦Decreased capacity for sending nerve impulses  Processing of info decreases  Conduction velocity decreases  Voluntary motor movement decreases  Reflex times increase 6

7 Cerebral Palsy Neuromuscular disability Infants and toddlers affected Voluntary muscles are poorly controlled or paralyzed Caused by brain damage either genetics or accidental 2 out of every 1000 newborn affected

8 Anencephaly Cerebrum and part of brain are never developed Newborns are the ones affected Caused by neural folds fail to fuse rostrally (fuse towards the head) Victims in “vegetative state” meaning that mental life is nonexistent Victims usually pass away Approx 1 out of every 68,000 affected

9 Spina bifida Incomplete formation of vertebral arches along the lumbosacral region (lower back) Children mainly affected (newborns) Spina bifida cystica: cyst protrudes from child’s back; can lead to: functionless spinal cord if not treated incontinence muscle paralysis renal failure urinary tract infection Spina bifida occulta: least serious form with only one or a few vertebrae and causes no neural problems

10 Alzheimer’ Disease Most common form of dementia (weakening of mind due to age) Mind literally deteriorates alongside the brain Causes not well understood Old people mainly affected 1 in 8 older Americans affected by AD Symptoms usually reveal during or after age 65: Confusion Mood Swings Trouble with language Long term memory loss

11 QUIZ TIME!!!!!

12 Which of the following is true about the aging of the nervous system? A) there’re no ways to slow down the deterioration of the nervous system. B) as you age, your brain and spinal cord lose nerve cells & weight C) average human’s nervous system ages at the same rate D) None of the Above

13 Which are true about Alzheimer’s Disease? A) It has a higher likelihood for older people during or after the age of 75 B) Symptoms are: aggression, memory loss, confusion etc. C) It stays the same as it progresses D) All of the above

14 All of the following are considered primary brain vesticles EXCEPT: A) Rhombencephalon B) Prosencephalon C) Metencephalon D) Mesencephalon

15 Which of the following is false about anencephaly? A) Victims are in the “vegetative state” B) caused by cerebrum and brain stem never developing C) little mental capabilities exist D) caused by neural folds failing to fuse rostrally

16 Spina Bifida Occulta is more serious than Spina Bifida Cystica True False