Nervous and sensory systems

First listen to the presentation: Nervous and sensory systems


1. Protective layers of the brain
What is the collective name for the protective layers of the brain? What are they each called?

Answer: The Meninges; pia mater; arachnoid mater; dura mater.











2. Fluid in the brain
What fluid is found in brain and spinal column? Where is this found in the brain? State two functions of this fluid.

Answer: Cerebrospinal fluid (CSF); located in the ventricles; protection and chemical stability.

3. The neurone
Name the main features of the neurone.

Answer: cell body; axon; dendrites; axon terminals (could include myelin sheath).







4. The action potential
Explain what happens in an action potential.

Answer: sodium ions flood into the nerve cell; the membrane potential is reversed (becomes positive); the action potential is transmitted along the cell (saltatory conduction); the sodium ions are pumped out and the resting potential is restored.






5. The synapse
What happens at a synapse?

Answer: nerve impulse arrives at pre-synapse; chemical (acetly choline) released into synaptic space; action potential triggered post-synapse; chemical is broken down and reabsorbed .






6. Saltatory conduction
Explain saltatory conduction.

Answer: tales place in myelinated nerves; faster than in unmyelinated nerves; depends on Nodes of Ranvier; action potential 'jumps' from node to node (ie Nodes of Ranvier).




7. Regions of the brain
Name the eight regions of the brain (half mark each).

Answer: frontal; motor cortex; sensory cortex; parietal lobe; temporal lobe; occipital lobe; cerebellum; brain stem.









8. Cranial nerves
What do cranial nerves mainly do?

Answer: eye movement; swallowing; smell; hearing.









9. Divisions of the nervous system
Name the two divisions of the peripheral nervous system and the sub-divisions of the division concerned with involuntary actions.

Answer: somatosensory and autonomic; and the autonomic is divided into the sympathetic and the parasympathetic systems.








10. Special senses
In addition to sight what are the other special senses?

Answer: hearing; touch; taste and smell.













11. The eye
What four structures of the eye does light have to travel through to reach the optic nerve?

Answer: cornea; aqueous humour; lens; vitreous humour.












12.The ear
What are the three bones of the inner ear and what are they called, collectively?

Answer: maleus; incus and stapes; ossicles.

Homeostasis

First, listen to the presentation: Homeostasis

1. Define 'homeostasis'.

Answer: The maintenance of a constant, internal environment.












2. What are the components of a homeostatic system?

Answer: sensor or receptor; control centre; effector; variable









3. Using blood glucose as an example explain how negative feedback works in the restoration of blood glucose levels after ingesting carbohydrates.

Answer: Following ingestion of the carbohydrates blood glucose levels rise, this is detected by the pancreas, insulin is released and blood glucose levels are lowered and insulin release is stopped by negative feedback.



4. Using blood pressure as an example identify the folowing: sensor or receptor; control centre; effector; variable.

Answer: sensor or receptor - baroreceptors ; control centre - medula oblongata/brain; effector - cardiovascular system; variable -
blood pressure.






5. Using falling blood pressure as an example explain how negative feedback works.

Answer: When blood pressure (BP) falls this is detected by the baroreceptors and the information is processed by the medulla oblongata. The cardiovascular system responds (increased heart rate and vasoconstriction) BP rises to within mormal limits and this stops the increase in BP through negative feedback.

From cells to system

First, listen to the presentation: From cells to systems

 1. Levels of organisation
What are the four levels of organisation between organelle and organism?

Answer: cell; tissue; organ; system.













2. Anatomical planes
Name the three planes through which the body can be viewed and if you were looking down on top view of, eg a slice of the brain, which plane would this be?

Answer: saggital, coronal and transverse; transverse.

3. Anatomical directions

Describe: the position of the legs relative to the head (while standing); the elbow relative to the hand; the scaplulae (shoulder blades) relative to the sternum (breatbone) and the nose relative to the ears.

Answer: inferior; proximal; posterior; medial.

4. The cell

Which structure surrounds and contains the cell?

Which structure contains the chromosomes?

Which structure is the 'power house' of the cell?

What substance are all the structure of the cell contained in?

Answer: plasma membrane; nucleus; mitochondrion; cytoplasm (click on the diagram to see all the labels).

5. Types of tissues

Name the four main tissue types.

Answer: nervous; muscle, connective, epithelial.

6. Epithelial tissue by layers

Name the three classifications of epithelial tissue by layers.  Of which type is the skin an example?

Answer: simple; stratified; pseudostratified. Stratified.

7. Epithelial tissue by cell shape

What are the three classifications of epithelial tissue by cell shape.  Of which type is the skin an example?

Answer: squamous; cuboidal; columnar. Squamous

8. Systems

Which systems contain the following:
brain and nerves

heart and blood vessels

muscles and bones

stomach and intestines

Answer: nervous system; cardiovascular system; skeletomuscular system; gastrointestinal system.

9. Osmosis

Describe osmosis.

Answer: The movement of water from a region of high concentration of water to a region of lower concentration of water through a semi-permeable membrane.

10. Diffusion

Compare and contrast diffusion, facilitated diffusion and active transport.

Answer: Diffusion only works down a concentration gradient; facilitated diffusion takes place across membranes at specific carrier sites but only down a concentration gradient; active transport takes place across membranes at specific carrier sites but works against a concentration gradient and requires energy in the form of ATP (click on the diagram to see an animation).