Summary
Summary Module 5.3: Animal response
- Module
- Module 5.3: Animal responses
- Institution
- OCR
OCR A level biology A Key concepts of the nervous system and fight or flight response with muscle contractions.
[Show more]
Seller
Follow
Content preview
ANIMAL RESPONSES Fight or flight- Threat detected by autonomic nervous system
Nervous system - Sympathetic pathway = neuronal pathway
Central nervous system = brain, spinal cord - Adrenal-cortical system = hormonal pathway
Peripheral = neuros connect CNS to body (sensory, motor)
> Somatic = conscious control
> Autonomic = subcon, to gland, smooth + cardiac mus
> Sympathetic = outcome ↑ activity (f or f)
> Parasympathetic = outcome ↓ activity
Structure of the brain
Physiological responses:
1) ↑ heart rate – pump oxygenated blood
2) Pupils dilate – improve vision
3) Arterioles in skin constrict – to major organs
Cerebrum = voluntary action, learning, memory, thoughts 4) ↑ blood glucose conc - ↑ respiration + energy
- Receives sensory info, send out to effector 5) Smooth muscles in airway relax – more O2
- Highly convoluted = SA, cerebral cortex = outer 6) Non essential systems shut down, difficulty focusing
Cerebellum = coordinates unconscious, balance, posture Adrenaline
Medulla oblongata = controls autonomic, heart, breathe 1) Adrenaline binds to receptor (hydrophil = surface)
Hypothalamus = blood monitor, hormone, sym/parasymp 2) Activates G protein, activates adenylyl cyclase
Pituitary gland = anterior = produce, posterior = store/rel 3) Activated enzyme converts ATP to cAMP which acts
as second messenger (cascade), protein kinase
Reflex actions 4) Liver cells glycogenolysis – gluc for resp + contraction
Skeletal muscle – rapid short contractions
Involuntary smooth muscle – slow over long time Heart rate
Medulla oblongata controls, autonomic
Reflex arc - ↑ heart rate – sympathetic – accelerator nerve
1) Receptor = stimuli + AP - ↓ heart rate – parasympathetic – vagus nerve
2) Sensory neurone = impulse to spinal cord
3) Relay neurone = connects sensory to motor Chemoreceptors
4) Motor = impulse to effector for response - Detect pH change (CO2)
- ↑ CO2 ↓ pH as carbonic acid formed
Survival - Low pH increases heart rate = more CO2 exhaled
- Reduce severity of damage + not overload - ↓ CO2, ↓ freq impulses to medulla oblongata + SAN
- Don’t have to learn – immediate protection
- Extremely fast – only 2 synapses Baroreceptors
Knew jerk reflex - In wall of aorta, detects blood pressure
- Circuit only to spinal cord - ↑ pressure, impulses to MO ↓ heart rate
- Helps maintain posture + balance subconsciously - Impulses along parasympathetic to SAN
- Extensor muscle contracts, relay inhibits antagonistic - ↓ pressure, impulses to MO ↑ heart rate
Blinking reflex Hormonal control
- Cornea stimulated, foreign bodies, sounds, light - Adrenaline + noradrenaline ↑ heart rate
- Cranial reflex = occurs in brain, consensual - ↑ freq of impulses by SAN (pacemaker)
- Test unconscious patients / whether brain dead
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller katieg1500. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
64450 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 15 years now