1. Nervous & Sensory Systems
by: Cindy Quisenberry

2. How does the nervous system control your body?
The nervous system directs the functions of all human body systems.
Every activity is controlled by some of the more than 100 billion nerve cells in the body.
CNS (Brain & Spinal Cord) – acts as a control center
PNS (Nerves) – carry messages to and from this center

3. Neurons (Nerve cells) – Basic Element of the Nervous System
Each nerve is a bundle of neurons (sends electrical messages to the body’s organs and muscles).
Each neuron consists of 3 parts:
The cell body – reach out to send or receive impulses.
Dendrites – conduct nerve impulses toward the cell body.
The axon – conducts nerve impulses away from the cell body.

4. Nerve Impulses What is the tissue called that covers the axon?
What is the space called where impulses jump between neurons?

5. Nerve Impulses What is the tissue called that covers the axon?
Myelin Sheath
What is the space called where impulses jump between neurons?
Synapse

6. Two Basic Properties of Neurons
Excitability – the ability to respond to a stimulus
Conductivity – the ability to transmit a signal

7. Three Types of Neurons
Efferent or Motor – convey information to the muscles and glands from the CNS
Afferent or Sensory – carry information from sensory receptors to the CNS
Interneurons – carry and process sensory information

8. Electrical Impulses to Organs & Muscles
Cells of the Body Release Electrical Energy After an External Stimuli or Stimulation from Internal Chemical Passes Through Nerve Cell Nerve Impulse Received by Tissues & Organs (Receptors) Transmitted to Other Receptors

9. Neuroglias Connect, protect, and remove debris from the system
Do not transmit impulses
Along with capillaries, these cells form the Blood Brain Barrier
Blood Brain Barrier – permits some chemical substances to reach the brain’s neurons while blocking most others

10. The Central Nervous System – Center of Control
Composed of brain and spinal cord.
Receives and interprets all stimuli and sends nerve impulses
Voluntary & Involuntary Movement
Brain has 4 major divisions:
Brainstem
Cerebellum
Cerebrum
Diencephalon

11. Cerebrum – 2 Hemispheres & 4 Lobes
Responsible for reasoning, thought, memory, judgment, speech, sensation, sight, smell, hearing, and voluntary body movement.
Includes the:
Frontal Lobe - voluntary motor movement, expression, moral behavior
Parietal Lobe - interprets senses and taste
Temporal Lobe - memory, equilibrium, emotion, and hearing
Occipital Lobe - vision, some forms of expression
Contains Cerebral Cortex (outer portion) – area of conscious decision making
Start Claymation

12. Divisions of the Brain

13. Central Nervous System
Brain Stem
Midbrain – concerned with visual reflexes
Pons – respiratory functions
Medulla Oblongata – contains centers that regulate heart and lung functions, swallowing, vomiting, coughing, and sneezing
Cerebellum
Coordinates Musculoskeletal Movement

14. Central Nervous System
Diencephalon
Thalamus
Hypothalamus
Integrates with the ANS to control: HR BP
Temp
Water & Electrolyte Balance
Digestion
Behavioral Responses
Grandular Activities

15. Cerebrospinal Fluid (CSF)
Between the area of the brain and the cranium
A water liquid that contains various compounds and flows throughout the brain and around the spinal cord
Cradles and cushions the brain
Ventricles in the brain also contain this fluid

16. Spinal Cord
Extends from the base of the brain to near the first lumbar vertebra
Contained within the vertebral column in a space called the vertebral canal
Protected by:
Vertebral Column
CSF
Spinal Meninges

17. Layers of the Meninges

18. The Meninges
Dura Mater – outer layer, covers the entire length of the spinal cord and contains channels for blood to enter brain tissue
Arachnoid Mater – middle layer, runs across the space containing CSF
Pia Mater – innermost layer, thin membrane containing blood vessels to nourish the spinal cord

19. What can we inject Into the epidual space?
Epidural Space - b/w the dura mater & the bones
What can we inject
Into the epidual space?

20. The Peripheral Nerves
Twelve pairs of cranial nerves carry impulses to and from the brain.
Thirty-one pairs of spinal nerves carry messages to and from the spinal cord and the body.
Contains 2 subsystems:
Somatic Nervous System
Autonomic Nervous System (ANS)

22. The Peripheral Nerves
The somatic nervous system receives and processes sensory input and excites the voluntary contraction of skeletal muscles.
The autonomic nervous system carries impulses from the central nervous system to glands, various involuntary muscles, cardiac muscle, and various membranes.
Divided into 2 Divisions
Sympathetic
Parasympathetic

23. The Peripheral Nerves
The somatic nervous system receives and processes sensory input and excites the voluntary contraction of skeletal muscles.
The autonomic nervous system carries impulses from the central nervous system to glands, various involuntary muscles, cardiac muscle, and various membranes.
Divided into 2 Divisions
Sympathetic
Parasympathetic

24. Autonomic Nervous System – both divisions play opposite roles
Sympathetic Division– operates under stress (fight or flight)
Parasympathetic Division– operates to keep the body in homeostasis, under normal conditions

25. Autonomic Nervous System – both divisions play opposite roles
What are the three parts of neurons?

26. Autonomic Nervous System – both divisions play opposite roles
What are the three parts of neurons?
Cell Body
Dendrites
Axon

27. Sensory System or Special Senses
The sensory system includes any organ or part that perceives or receives stimuli from the outside world.

28. Sensory System Sight—the Eye Hearing and Equilibrium—the Ear
Touch, Pain, and Temperature—the Skin
Smell—the Nose
Taste—the Tongue and Oral Cavity

29. Major Parts of the Sensory System
Sight - the Eye
Hearing – the Ears
Touch - the Skin
Smell - the Nose
Taste - the Mouth

30. Sight – The Eye Outer Layer
The sclera – supports the eyeball and nourishes the cornea
Cornea – transparent layer where light is bent (refracted) as it enters the eye
Middle Layer
Choroid – focuses the eye
Interior Layer
Retina – decodes light waves and sends the info to the brain
Rods – black and white
Cones - color
Optic Disk – where the retina connects to the nerve

31. Sight – The Eye

32. Chambers of the Eye Anterior Chamber Posterior Chamber
Lies between the cornea and iris
Nourishes the lens and cornea
Maintains constant pressure of the eyeball
Posterior Chamber
Lies between the iris and the lens
Vitreous Chamber – occupies about 80% of the space in the eyeball
Nourishes parts of the eye and maintains structure to keep the eye from collapsing

33. Chambers of the Eye
Eyelids
Eyebrows and Eyelashes
Lacrimal Glands

34. The Ear Major divisions of the ear The external ear, or pinna.
The middle ear includes the eardrum, or tympanic membrane.
The inner ear, which contains three semicircular canals and the cochlea.

35. The Ear

36. Smell – The Nose Olfactory relates to the sense of smell.
The sense of smell is activated by receptors located at the top of the nasal cavity.
The receptors are nerve cells covered with hairlike cilia that send messages to the brain

37. Taste - the Tongue and Oral Cavity
Taste buds sense the taste of food.
Located on the surface of the tongue in small raised structures called papillae.
Four main types of taste buds to match taste sensations
Sweet
Sour
Salty
Bitter

38. Taste

39. The Sensory
Which part of the eye decodes light waves and sends the information to the brain?

40. The Sensory
Which part of the eye decodes light waves and sends the information to the brain?
The retina