5.1.5 Plant and animal responses Flashcards
Which neurotransmitter is present in the somatic nervous system?
Acetylcholine - stimulatory effect
Which neurotransmitter is present in the sympathetic system?
Noradrenaline
Which neurotransmitter is present in the parasympathetic system?
Acetylcholine
What is the function of the cerebrum?
Controls voluntary actions such as learning, memory, personality and conscious thought
What is the function of the cerebellum?
Controls unconscious functions such as balance and non voluntary movement
What is the function of the medulla oblongata?
Used in autonomic control e.g. controls heart rate and breathing rate
What is the function of the hypothalamus?
Regulatory centre for temperature and water balance
What is the function of the pituitary gland?
Stores and releases hormone
What is the function of the anterior (front) pituitary?
Produces FSH
What is the function of the posterior (back) pituitary?
Stores and releases hormones produced by hypothalamus e.g. ADH
What is the pathway of a reflex arc?
Receptor -> sensory neurone -> relay neurone -> motor neurone
What is the stimulus in the knee jerk reflex?
Tapping the patella and causing the patellar tendon to stretch
In the knee jerk reflex the ______ muscle contracts and the ______ relaxes causing the leg to kick
Extensor
Flexor
What is the stimulus in the blinking reflex?
- Cornea being touched (corneal reflex)
- Loud sound
- Bright light (optical reflex)
What type of reflex is the knee jerk reflex?
Spinal (occurs in the spinal cord)
What type of reflex is the blinking reflex?
Cranial (occurs in the brain)
What is the effector in the blinking reflex?
Eyelid
What is the importance of reflexes?
- Minimises harm to body by being a very fast response
- Doesn’t have to be learnt so provides immediate protection form birth
- Doesn’t require conscious thought so brain is not overstimulated
What are the three types of muscles?
- Skeletal muscle
- Cardiac muscle
- Involuntary muscle (smooth muscle)
What is the structure and arrangement of skeletal muscle?
- Striated fibres (lines on fibres)
- Tubular fibres which are multinucleated (more than one nucleus) and regularly arranged
What is the contraction length and speed in skeletal muscle?
Short and rapid in one direction
What is the structure and arrangement of cardiac muscle?
- Specialised striated fibres (less lines on fibres than skeletal)
- Branched fibres which are uninucleated (only one nucleus)
What is the structure and arrangement of involuntary muscle?
- Non-striated fibres
- Spindle shaped fibres which are uninucleated (only one nucleus) with no regular arrangement
What is the contraction length and speed in involuntary muscle?
Long and slow in different directions
What is the plasma membrane which encloses muscle fibres?
Sarcolemma
What is the shared cytoplasm between muscle fibres called?
Sarcoplasm
What are T tubules and what is their function?
Parts of the sarcolemma that fold in to help spread electrical impulse through sarcoplasm so entire fibre can contract
Why do muscle fibres have a lot of mitochondria?
Provide ATP needed for muscle contraction
What does the sarcoplasmic reticulum contain?
Calcium ions required for muscle contraction
What types of protein filaments are myofibrils made of?
Actin - thinner
Myosin - thicker
What are I bands?
The lighter coloured bands where only actin is present and there is no overlap between the myosin filaments and actin
What are A bands?
The darker coloured bands where there is myosin present and an overlap between myosin filaments and actin
What is a Z line?
Line found at the centre of the light band
What is the distance between adjacent Z lines called?
Sarcomere
What is the H zone?
Lighter coloured region in centre of dark band where only myosin filaments are present
