Integration of body systems

Explain how chemoreceptors work.


If CO₂ increases (e.g., during exercise):

Blood becomes more acidic.

Chemoreceptors detect the low pH and the signal is sent to the cardiovascular center of the medulla.

The medulla sends sympathetic impulses to the SA node to increase the heart rate and stroke volume.

More blood is pumped to the lungs, enhancing gas exchange

What is White Matter composed of and what is its function?


Myelinated axons; responsible for communication pathways.

What is Grey Matter composed of and what is its function?


Cell bodies; responsible for processing.

What does the Medulla Oblongata control?


Heart rate and breathing.

What is the function of the Cerebrum?


Conscious thought and voluntary actions.

What is the function of the Cerebellum?


Balance, coordination, and motor learning.

Compare the Somatic Nervous System and the Autonomic Nervous System.


Somatic Nervous System:

Controls voluntary actions

Uses a single, myelinated motor neuron

Provides fast responses

Example: Controls skeletal muscles

Autonomic Nervous System:

Controls involuntary actions

Uses two neurons connected at a ganglion

Provides slower responses

Example: Regulates heart rate and digestion

What are the two divisions of the Autonomic Nervous System?


Sympathetic and Parasympathetic

Role of interneurons.


Connect sensory and motor neurons within CNS.

Role of motor neurons.


Carries impulses from CNS to effectors.

Role of sensory neurons.


Carry impulses from receptors to CNS.

What are the three types of neurones?


Sensory Neurons

Motor Neurons

Interneurons

What is the hierarchy of biological organisation?


Cells → Tissues → Organs → Organ Systems → Organism

Example of emergent properties.


Consciousness from many neurones working together.

How do barorecptors work?


When blood pressure decreases, baroreceptors detect that and sends an impulse to the medulla. The medulla responds by sending impulses by a sympathetic neuron to the SA node to increase the heart rate and stroke volume.

If blood pressure is high: parasympathetic neuron to decrease heart rate.

What is the function of the enteric nervous system (ENS)?


Controls digestion and coordinates peristalsis independently of the CNS.

What do baroreceptors detect?


Changes in blood pressure.

What hormone regulates circadian rhythms and which gland secretes it?


Melatonin, secreted by the pineal gland in response to darkness.

Describe the pathway of a reflex arc.


Stimulus → Sensory neuron → Interneuron (spinal cord) → Motor neuron → Effector → Response.

What is the role of the hypothalamus in homeostasis?


It links the nervous and endocrine systems, controlling basic drives and regulating the pituitary gland.

Where is epinephrine secreted from?

Adrenal glands.