C3.1 Integration of body systems

What are the roles of nerves and hormones in the integration of body systems?

Nerves provide rapid and specific communication via electrical impulses, while hormones enable slower, systemic coordination through chemical signals.

How do feedback mechanisms regulate body systems?

Feedback mechanisms maintain homeostasis by adjusting system functions based on sensory input, ensuring balance within the body.

Why do multicellular organisms require system integration?

System integration allows coordination of multiple specialized systems, enabling efficient operation and survival in complex environments.

Endocrine system

• Collection of ductless glands producing hormones

• Composed of glands

• Hormones transmit signals to the target organs

• Hormones carried in the blood

• Whole system is not physically connected

• Signals take more time to reach effector organ

• Effect is widespread

• Controls growth, hydration level, heat productivity, sexual maturity, production of gametes

Nervous system

• Collection of nerve cells and neurotransmitters

• Composed of brain, spinal cord, peripheral nerves

• Neurotransmitters used to transmit signals to effector organs

• Signals transmitted through nerve cells

• Whole system is physically connected

• Rapid signal transmission

• Effect is localised

• Controls muscle movement, heartbeat, digestion, breathing, senses, speech and memory

blood

transport medium for most multicellular organisms

photoreceptors

located in retina of the eys for visual infromation

chemoreceptros

many located on our tongue for tasting. check things like co2 levels and blood ph

thermoreceptors

located in the skin to procide informationon changes in temp

osmoreceptors

located in the carotid arteries and the hypothalamus. sense solutes and water content of the blood

spinal nerves

there are 31 pairs which emerge directly from the spinal cord

cranial nerves

12 paired nerve endings coming from the brain through the brain stem

cerebellum

The cerebellum coordinates movement and is involved in learned movements, balance and equilibrium

cerebrum

The cerebrum sits at the topmost part of the brain and is the source of conscious thoughts and actions. It holds your memories and allows you to plan, imagine, and think. it is split into 2 halves, (hemispheres).

hypothalamus

Maintains homeostasis via coordination of the nervous and endocrine systems, produces hormones secreted by posterior pituitary

pitutary gland

Produces and secretes hormones regulating many body functions, e.g. such as ADH

medulla obolngata

Controls automatic and homeostatic activities, such as swallowing, digestion and vomiting, and breathing and heart rate.

cerebral hemisphere

Act as the integration centre for highly complex functions, such as learning, memory and emotion.

spinal cord

The spinal cord acts as an integrating centre only for unconscious processes, those that we do not have to think about such as reflexes.

the brain

The brain acts as an integrating centre for both conscious and unconscious processes.

motor neurons

carry impulse from central nervous system to effector organs

sensory neurons

carry information from the receptors to the CNS.

motor cortex

the protion of the cerebrum that sends action potention to motor neurons

motor end plates

Motor neurons form synapses with muscle fibres at neuromuscular junctions

white matter

composed of axons of neurons and carries neural impulses to and from the brain

grey matter

contains neurons and synapeses

pain relfex arc

an exmample of an involuntary response

what happens when you hold your hand in open flame

• action potential in your finger travel through your hand and eventually joi a spinal nerve

• after entering spinal cord, the afferent neuron synapses with ashort interneuron loacted in grey matter on spinal cord

• interneuron synapses with a motor neuron resulting in you mvoing hand away from open flame

movement

• as movement begins, the cerebellum recieves feednack impulses from area that is moving

• cerebellum then sends out impulses to coordinate the movement

• leads to coordinated movement

circadian rythm

any pattern of behavoiur or physisology that is based on a24 hour cycle

melatonin

• produced by pineal gland

• targets the pituitary gland and others

• effect: synchronization of circadian rythms including sleep timing and blood pressurre

• melatonin peaks in the middle of the night

epinephrine

adrenaline, realsed when we encounter a stressful situation. it is a hormone. it is secreated directly into the blood stream from adrenal glands

how does adrenaline prepare you for fight or flight

• increased and strengthened heart contractions

• cardiac output increases

• increased blood flow to muscles to provide o2

• constricted blod flow to less vital organs

• increase in glucose by dialating blood vessels in muscule and liver

• dialted bronchi leading to lungs increasing airflow, increasing oxygen given to muscules

• pupils become dialated

glandular cells

these cells of the hypothalamus produce hormones that either stimulate hormone release by pituitary glands or inhibit it

ADH

helps control homeostatic levels of water in the body. works using negative feedback

baroreceptors

monitor blood pressure. they exist in aorta, cartoid artery

autonomic nervous system

repsonds automatically to changes in body condition

heart pacemakers

sinoatrial node and atrioventicular node. pacemaker is connected with the nervous system and responds to changes accordingly

increased blood pressure

• wall of the artery is distended or stretched outward

• results in an increase in. the rate of action potentials sent to the medulla

• medulla responds by sending aimpulses to SA node to decrease heart rate and decrease force of contraction

• decrease in heart rate

decreased blood pressure

• decrease in action potentials sent to the medulla

• leads to an increase in heart rate

why co2 control is crucial

increased co2 concentration can decrease blood ph and can lead to death or feeling exetremely unwell

co2 and ventilation

• when excerising a lot, we increase respiaration, producing more co2 which can turn our blood more acid

• to prevent this, we hyperventilate to get enough oxyfgen to cancel out co2

enteric nervous system

keeps the food during digestion moving along alimentary canal

peristalisis

the movement of food. it is controled by enteric nervous system

movement of food in intestines

• when food moves in intenstine, it stretches the walls, stimulating stretching receptor in enteric nervous system

• 2 neros are then released

• 1 stimulates the the smooth muschule behind food to contract by releasing excitatory neutrotransmitter

• the other one relxases smooth muscle