5.5 ANIMAL RESPONSE Flashcards
Draw the organisation of the mammalian nervous system
Define central nervous system
- The brain and spinal cord
Define peripheral nervous system
- The motor and sensory neurons connecting the sensory receptors and effectors to the CNS
Define somatic nervous system
- The motor neurones under conscious control
Define autonomic nervous system
- The motor neurones under the control of the involuntary motor activities of the body
State the neurone(s) that make us the central nervous system
1) Relay neurones
State the neurone(s) that make us the peripheral nervous system
1) Sensory neurones
2) Motor neurones
Which type of neurone is mainly un-myelinated
- Relay neurones
State the role of myelinated neurones
- They carry action potentials up and down the spinal cord for rapid communication over long distances
Describe the sensory nervous system
- The sensory neurones that conduct action potentials from the sensory receptors to the CNS
Describe the motor nervous system
- Conducts action potentials form the CNS to effectors
Describe somatic nervous system
- Motor neurones that conduct action potentials from CNS to effector under conscious/voluntary control (e.g skeletal muscles)
- The neurones are myelinated for rapid response
- Always one motor neurone connects the CNS to the effector
Describe autonomic nervous system
- Motor neurones that conduct action potentials from CNS to effector under involuntary control (e.g glands, cardiac muscle/smooth muscle of the heart, the airways)
- Most neurones are un-myelinated as not a rapid response
- Are atleast two motor neurones connects the CNS to the effector (ganglia)
Compare in detail the sympathetic and parasympathetic system
Draw the human brain
Define cerebellum
- Region that co-ordinates balance and controls fine movements
Define cerebrum
- Divided into two cerebral hemispheres
- Organises conscious thought and memory
Define hypothalamus
- Co-ordinates homeostatic responses
Define medulla oblongata
- Controls autonomic responses/psycological processes
Define pituatry gland
- Endocrine gland at the base of the brain, attached to the hypothalamus
- The anterior lobe secretes hormones
- The posterior lobe stores and releases hormones made in the hypothalamus
Describe the cerebrum
- Controls: conscious thought, conscious actions, emotions, intelligence/decision making, factual memory
- Divided into two hemispheres
- Subdivided into sensory, association and motor areas
Describe the cerebellum
- Receives information from the sensory receptors
- Controls: maintanance of body position/balance, judging position of objects, contraction/relaxation of antagonistic skeletal muscles
Describe the hypothalamus/pituatry gland complex
Hypothalamus:
1) Temperature regulation - detects changes in body temp and also receives sensory input from temperature recptors in the skin, then initiates response via either the neuronal or hormonal system
2) Osmoregulation - contains osmoreceptors that monitor wtaer potential of the blood, the pituatry gland then initiates response via the hormonal system
Pituatry gland: (two lobes)
1) Posterior lobe is connected to the hypothalamus via specialised neurosecretory cells, hormones like ADH are manufactured by hypothalamus, pass down the neurosecretory cells and released into the blood by the pituatry gland
2) Anterior lobe produces its own hormones which are released into blood in response to releasing factors produced by hypothalamus (anterior lobe responds to stress/growth/reproduction)
Describe the medulla oblongata
-
Controls the non-skeletal muscles (cardiac muscles and involuntary smooth muscles) by sending action potentails throughout the autonomic nervous system
1) Cardiac centre - which regulates heart rate
2) Vasmotor centre - which regulates circulation and blood pressure
3) Respiratory centre - which regulates rate and depth of breathing
Define reflex action
- Responses to chnages in the external environment WITHOUT brain processing
- For survival/ to get out of danger/ avoid damage/ maintain balance
State the pathway of reflex actions
1) Sensory neurone
2) Relay neurone
3) Motor neurone
State the two types of blinking relfex
- Can be corneal reflex
- Can be optical reflex
Define knee jerk reflex
- Straightens the leg when the tendon below the knee cap is tapped
Describe the optical reflex
- Slower than the corneal reflex
- Protects the light-sensitive retina cells from damage
- Stimulus is detected by the retina
- Reflex is meditated by the optical centre at the cerebral cortex
Describe the corneal reflex
1:
- Action potential from the cornea is carried by a sensory neurone which enters the pons
- This passes the action potential to a relay neurone then to a motor neurone
- The motor neurone then passes the action potential to facial muscles
- Causes both eyes to blink
2:
- The sensory neurone also passes the action potential to myelinated sensory neurones which go to the cerebral cortex
- This can send inhibitory signals to the motor centre in the pons
- This can override the reflex as these sensory neurones are myelinated, so more rapid than non-myelinated relay neurones
- Causes both eyes to blink
Describe
