Chapter 3a-Physical.pdf

Chapter 3-Physical Body Changes Body size The First Two Years – Body and – Average weight Mind...

Chapter 3-Physical Body Changes Body size The First Two Years – Body and – Average weight Mind At birth: 7 pounds At 24 months: 28 pounds Average length At birth: 20 inches At 24 months: 34 inches – These numbers are norms or average measurements 1 2 Sequences of Physical Development Body Size Cephalocaudal Development Most notable time for physical changes – In first year, height increases about 1 inch – Growth proceeds from the upper part of per month the head to the lower parts of the body – birth weight usually doubles by 4 months and triples by end of first year Proximodistal Development – In second year, height increases 4-6 inches – Growth proceeds from the trunk outward – Weight increases 4-7 pounds from body’s central axis toward periphery Usually grow in spurts 3 4 Reflexes Weight Percentiles The Newborn The first movements are not skills but reflexes, involuntary responses to a particular stimulus. https://www.youtube.com/watch?v=hDiqATUYjX4 https://www.youtube.com/watch?v=gyVLD0hl0XY&t=2s 5 6 1  What Kinds of Reflexes Are Shown What Kinds of Reflexes Are Shown by Neonates? by Neonates? Rooting Moro or startle reflex – Baby turns head and mouth toward stimulus that – Back arches, legs and arms are flung out and then strokes the cheek, chin, or corner of mouth brought back toward chest into a hugging motion – Facilities finding mother’s nipple for sucking – Occurs when baby’s position is suddenly changed or head and neck support is lost Sucking – Elicited by loud noises or bumping the baby – Babies will suck almost any object that touches the lips – Usually lost 6 to 7 months after birth – Will become replaced by voluntary sucking 7 8 What Kinds of Reflexes Are Shown What Kinds of Reflexes Are Shown by Neonates? by Neonates? Grasping or palmar reflex Stepping reflex – Using four fingers, babies grasp fingers/objects – Mimics walking when held under arms pressed against the palms of their hands – Usually disappears by 3 or 4 months – Most babies can support their own weight – Usually lost by 3 to 4 months Babinski reflex – Replaced by voluntary grasping at 5 to 6 months – Fans or spreads toes in response to stroking foot – Usually disappears at end of first year 9 10 Newborn Vision SENSES and Face Recognition Hearing develops during the last trimester of pregnancy and is already quite acute at birth Vision is the least mature sense at birth. – Newborns focus only on objects between 4 and 30 inches away. – Binocular vision, the ability to coordinate the two eyes to see one image, appears at 3 months. – Show preferences for human faces Source: © 2003 PhotoDisc 11 12 2  Newborn Vision Touch,Smell and Taste and Face Recognition Touch - Comforted by human touch; feel pain Smell –Well-developed at birth –Demonstrate aversion for noxious and preference for pleasant odors –Recognize familiar odors Taste –Sensitive to different tastes –Demonstrate facial expressions in response to tastes –Prefer sweet tastes Source: © 2003 PhotoDisc 13 14 Facial Expressions Elicited by Sweet, Sour, and Bitter Solutions Sleep Average newborn sleeps 16 hours per day Specifics vary due to age, characteristics, and social environment Ample sleep correlates with normal brain maturation, learning, emotional regulation, academic success and psychological adjustment Needed for rapid growth 15 16 MOTOR DEVELOPMENT 17 18 3  What Is Motor Development? Motor Skills: Gross Motor Skills Motor development is the activity of muscles, and Gross motor skills changes in posture, movement, and coordination – Physical abilities Follows cephalocaudal and proximodistal patterns involving large body – Lifting and holding head before torso movements, such as – Voluntary reaching walking and jumping – Locomotion 19 20 Gross Motor Skills Gross Motor Skills Gross motor skills Sequence of emerging skills – Sitting unsupported – Every basic motor skill develops over the first – Standing, holding on two years of life. – Crawling (creeping) – Course of development – Standing, not holding on Cephalocaudal (head-down) and proximodistal – Walking well (center-out) direction – Walking backward – Running – Jumping up 21 22 Age Norms (in Months) for Gross Motor Skills* Belly Time & Crawling 3 – 7 months 23 24 4  Creeping Crawling & Creeping Belly time for infants and crawling are important for optimal development: Calms – builds muscles that help breathing Helps sitting – strengthens stomach muscles Helps coordination Improves handwriting – develops arm stability Helps develop fine motor coordination Helps in developing reading skills – using both sides of brain 7-10 months 25 26 Motor Skills: Fine Walking Motor Skills Fine motor skills – Physical abilities involving small body movements, especially of the hands and fingers, such as drawing and picking up a coin 11-13 months 27 28 Fine Motor Skills Fine Motor Skills Sequence of emerging skills 3 mos – Clumsy swipe – Grasping rattle 4 mos – Voluntary grasp; ulnar grasp – Reaching to hold object 4-6 mos – grab & hold; transfer between – Thumb-and-finger grasping hands – Stacking two blocks 7-12 mos – pincer grasp – Imitating vertical line 29 30 5  Pincer Grasp DEVELOPMENT OF BRAIN & NERVOUS SYSTEM 31 32 The Brain Growth in Infancy Command center of organism Head-sparing – Brain of neonate weighs less than one pound – Biological mechanism – By first birthday, the brain triples in weight, – Protects the brain reaching nearly 70% of adult weight when malnutrition – Prenatal and postnatal brain growth (measured disrupts body growth by head circumference) is crucial for later – Brain is the last part of cognition the body to be damaged by malnutrition 33 34 Human Brain Neurons Basic cells of nervous system (brain, spinal cord, nerves to/from organs, muscles, sensory receptors, etc) – Receive and transmit messages Neurons vary according to function and location, but all contain – Cell Body – Dendrites – Axon Neurotransmitters – chemicals that transmit messages between neurons 35 36 6  Neural Communication Connections in the Brain 37 38 Neuron Connections Neuroscience Vocabulary The color staining on this photo makes it obvious that the two cell bodies of neurons (stained chartreuse) grow axons – Neuron and dendrites to each other’s neurons. One of billions of nerve cells in the central nervous This tangle is repeated thousands of times in every human system (CNS). brain. – Axon Throughout life, those fragile dendrites will grow or disappear, as the person continues thinking. Fiber that extends from a neuron and transmits electrochemical impulses from that neuron to the dendrites of other neurons. – Dendrite Fiber that extends from a neuron and receives electrochemical impulses transmitted from other neurons via their axons; transient exuberance. 39 40 Neuroscience Vocabulary Neuroscience Vocabulary – Synapse – Limbic system Intersection between the axon of one neuron and the Parts of brain that interact to produce emotions, dendrites of other neurons. including amygdala, hypothalamus, and hippocampus. – Neurotransmitter Many other parts of brain also are involved with emotions. Brain chemical that carries information from the axon of a sending neuron to the dendrites of a receiving – Prefrontal cortex neuron. Area of the cortex at the very front of the brain – Cortex that specializes in anticipation, planning, and impulse control Outer layers of the brain where most thinking, feeling, and sensing occurs. – Amygdala Tiny brain structure that registers emotions, particularly fear and anxiety. 41 42 7  Neuroscience Vocabulary Exuberance – Hippocampus Brain structure that is a central processor of At birth more than 100 billion neurons memory, especially memory for locations. are present – Cortisol Primary stress hormone; fluctuations in the body’s Phenomenal growth is referred to as cortisol level affect human emotions. transient exuberance—fivefold – Pituitary increase in dendrites in first 2 years Gland in the brain that responds to a signal from the hypothalamus by producing many hormones, including those that regulate growth and that control other glands, among them the adrenal and sex glands. 43 44 Increases in Neural Connections in the Brain How Do Neurons Develop? As child grows – Axons grow in length – Dendrites proliferate (grow and increase) – Connection networks become more complex Myelin (produced by glial cells) Fatty tissue that covers axons – Makes messages more efficient – Myelination occurs with maturation Figure 5.6 45 46 Harming the Infant Brain Experience Enhances the Brain, cont. Infants need stimulation William Greenough identified 2 – Playing, allowing varied sensations, and encouraging movement is necessary for brain connections. experience-related parts of brain growth Stress and the brain – experience-expectant brain functions – Overabundance of stress hormones damages later brain require basic common experiences to develop functioning. normally Infants need protection – Shaken baby syndrome is a life-threatening injury that – experience-dependent brain functions occurs when an infant is forcefully shaken back and depend on particular and variable experiences to forth. This motion ruptures blood vessels in the brain and develop breaks neural connections. 47 48 8  Experience Enhances the Brain Human brains are designed for expected experiences – how the brain is structured and connected will depend on those experiences – the brain expects certain experiences at certain ages 49 9