5.5 Animal Responses Flashcards
What is the central nervous system (CNS) made up of?
The brain and the spinal cord
What is the somatic nervous system?
It controls conscious activities, e.g. running
What is the sympathetic nervous system?
This activates the fight or flight response
What neurotransmitter is used in the sympathetic nervous system?
Noradrenaline
What is the peripheral nervous system?
Made up of the neurones that connect the CNS to the rest of the body, and contains the autonomic, sympathetic and parasympathetic nervous system.
What is the autonomic nervous system?
It controls unconscious activities, e.g. digestion and contains the sympathetic and parasympathetic nervous system
What neurotransmitter is used in the parasympathetic nervous system?
Acetylcholine
What is the parasympathetic nervous system?
It calms the body down, and reverse the effects of the fight or flight response
What is the function of the hypothalamus?
Controls body temperature and produces hormones that control the pituitary gland
What is the function of the cerebrum?
Involved in vision, hearing, learning and thinking.
What is the cerebrum divided into?
2 halves called cerebral hemispheres
What is the cerebral cortex?
The thin outer layer of the cerebrum which is highly folded
What is the function of the pituitary gland?
Controlled by the hypothalamus, it releases hormones and stimulates other glands e.g. adrenal gland
What is the function of the medulla oblongata?
Controls breathing rate and heart rate
What is the function of the cerebellum?
Involved with muscle coordination, posture, and balance.
What is a reflex?
When the body responds to a stimulus without making a conscious decision to respond.
What activates the fight or flight response?
When an organism is threatened
What are the 5 responses due to adrenaline?
- Increased heart rate
- Breathe deeper
- Glycogen converted to glucose
- Vasoconstriction at skin, blood diverted to heart, lungs and skeletal muscles
- Erector pili muscles in skin contract making hair stand up
What is a baroreceptor?
They detect changes in blood pressure in aorta and vena cava
What are thick myofilaments made of?
The protein myosin
What are thin myofilaments made of?
The protein actin
Dark bands contain which protein?
Actin
What is a neurone?
A specialised cell that transmits action potentials throughout the body
What is glial cell?
A specialised cell for assisting neuronal function, with many different types
What is a nerve?
A bundle of neurones
What is the frontal lobe involved with?
Emotions, problem solving, reasoning, speech and movement
What is the paretal lobe involved with?
Perception of stimuli- e.g. touch, pressure, temperature and pain
What is the temperal lobe involved with?
Perception, stimuli and memory (hippocampus)
What is the occipital lobe involved with?
Vision
What is the diencephalon?
Folded space that contains the hypothalamus and pituitary gland
What is the meninges?
Membrane which surrounds the brain, protecting from infection and trauma
What does cerebral-spinal fluid do?
Fills spaces to cushion the brain
What is a cortex?
A highly folded nervous tissue with large surface area for connections to be made
Why are reflexes useful?
Because time isn’t spent deciding how to respond, the response is much quicker
Why is the blinking reflex useful?
The body will automatically blink the eye to protect it from potential damage
Sensory neurones take an action potential from a _______ to the ______.
Receptor to the CNS
Relay neurones connect __________ neurones and __________ neurones
Sensory neurones to motor neurones
What muscles move the eye lids?
Orbicularis oculi muscles
Why is the knee jerk reflex useful?
It works to quickly straighten your leg if the quadricep is stretched to maintain balance.
What detects the muscle being stretched? (Knee jerk reflex)
Stretch receptors in quadriceps muscle
There is no _______ neurone involved in the knee jerk reflex.
Relay neurone
What is the effector in the knee jerk reflex?
The quadriceps muscle
The ________ and ________ systems coordinate the fight or flight response.
Neuronal and hormonal
What gland releases ACTH?
Pituitary gland
What does the hormone ACTH do?
It causes the cortex of the adrenal gland to release steroid hormones
Where is adrenaline released from?
The medulla region of the adrenal gland.
What is the conversion of glycogen to glucose called?
Glycogenolysis
What does the SAN do?
It generates electrical impulses that cause cardiac muscles to contract?
What controls the rate that the SAN fires (heart rate)?
The medulla
Why do animals need to alter their heart rate in response to stimuli?
Make sure the heart rate is enough to supply the body with enough oxygen
What are chemoreceptors
Chemical receptors that monitor oxygen and carbon dioxide levels and pH in the blood
What is secreted when baroreceptors detect high blood pressure?
Acetylcholine
What is secreted when baroreceptors detect low blood pressure?
Noradrenaline
What is secreted when chemoreceptors detect high O2 levels in the blood?
Acetylcholine
What is secreted when chemoreceptors detect low blood O2?
Noradrenaline
How does adrenaline increase heart rate?
It binds to specific receptors in the heart which cause cardiac muscle to contact more frequently and with more force
What can be used to study brain activity?
MRI or PET
Why does the sympathetic nervous system relax the bladder / bowels?
To dump mass to allow a faster escape
Why does the sympathetic nervous system inhibit digestive action?
To divert blood and energy to muscles for fight or flight
How does the heart know to alter its contraction rate?
The cardiovascular centre in the medulla picks up on stimuli, or stretch receptors
What does adrenal cyclase do?
Converts ATP > cAMP
What shape do smooth muscle fibres have?
Spindle shape with pointed ends
Why is involuntary muscle smooth?
Doesn’t have the striated appearance
Where is smooth muscle found?
In the walls of hollow organs such as the gut and blood vessels
Smooth muscle cells contain bundles of _________ and _________.
Actin and myosin
How do smooth muscles contract?
Slowly and regularly and doesn’t quickly fatigue
What does myogenic mean?
Contracts on its own
Where is cardiac muscle found?
Muscular walls of the heart
What is the structure of cardiac muscle?
Long muscle fibres with cross bridges forming intercalated discs
Why does cardiac muscle form intercalated discs?
They create low electrical resistance so nerve impulses pass easily and evenly between cells
How many nuclei do smooth muscle fibres have?
1
How many nuclei do cardiac muscle fibres have?
1
What shape are cardiac muscle fibres?
Cylindrical
How do cardiac muscles contract?
Rhythmically and don’t fatigue
What are the dark and light bands on a microscope image of a skeletal muscle?
Dark- A bands
Light- I bands
How many nuclei are in a skeletal muscle fibre?
Many
What are quickly contracting skeletal muscles for?
Speed and strength - but fatigue quickly
What muscles are used for endurance and posture?
Slow contracting, slow fatigue skeletal muscles
What is a sarcolemma?
Striated muscle cell membrane
What is a sarcoplasm?
Specialised skeletal muscle cell cytoplasm
How is the sarcoplasm specialised?
Contains many mitochondria and and sarcoplasmic reticulum
What is a sarcoplasmic reticulum?
Specialised endoplasmic reticulum in skeletal muscle cells
What are myofibrils?
Cylindrical structure extending along muscle fibre containing protein filaments actin and myosin
What are sarcomeres?
Myofibrils divided into a chain of subunits
What is the neuromuscular junction?
The junction between the nervous system and muscle
How do transverse (T) tubules allow electrical impulses to reach the whole muscle fibre?
The sarcolemma folds inwards across the muscle fibre and stick to the sarcoplasm
What does the sarcoplasmic reticulum do?
Stores and releases Ca2+ ions that are needed for muscle contraction
What are thick myofilaments made of?
The protein myosin
What are thin myofilaments made of?
The protein actin
What do A bands contain?
Thin myosin filaments and some overlapping actin filaments
What do I bands contain?
Thin actin filaments
What is the Z line?
The ends of the sarcomere
What is the M line?
The middle of each sarcomere, and the middle of myosin filaments
What is the H zone?
Contains myosin filaments
When a sarcomere contracts what happens to the A band?
Stays the same length
What happens to the I band when the sarcomere contracts?
It gets shorter
What happens to the H zones when the sarcomere contracts?
Get shorter
