LE5 Compana Lab

Cardiovascular system

• also called circulatory system

• organ system responsible for transporting materials

• delivers oxygen and nutrients to tissues

• removes carbon dioxide and wastes

heart, blood, blood vessels

Major parts of the cardiovascular system

1. Heart

2. Arteries, Veins, Capillaries

3. Blood 

Parts of the Cardiovascular System

Heart

pumps the blood

Arteries

carry blood away from the heart

Veins

carry blood back to the heart

Capillaries

thin vessels for gas exchange

Blood

carries oxygen, nutrients, and wastes

Heart

• four chambers

• has 2 atria (receiving chambers)

• has 2 ventricles (pumping chambers)

• apex is always to the left

• walls are muscular to create pressure

• more chambers = more efficient pumping

• valves ensure blood flows one way (unidirectional)

because it pumps blood to the whole body, not just the lungs. Thicker walls for more pressure

why is the left ventricle stronger than the right

valves

ensure blood flows one way

Location: Between right atrium and right ventricle

Function: Prevents backflow from RV → RA

Location and function of tricuspid valve

Location: Between right ventricle and pulmonary artery

Function: allows blood to exit to lungs: prevents backflow into RV

Location and function of Pulmonary valve

Location: Between left atrium and left ventricle

Function: Prevents backflow from LV → LA

Location and function of Mitral (Bicuspid) Valve

Location: Between left ventricle and aorta

Function: Allows blood to exit to body; prevents backflow into LV

Location and function of Aortic valve

“lub” is the mitral and tricuspid valves closing, and the “dub” is the aortic and pulmonary valves closing

why does the heart make the lub-dub sound

From the body → Through the heart → To the lungs

Body → vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs (to get oxygen again)

Pathway of deoxygenated blood

From the lungs → through the heart → To the body 

Lungs → Pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → body

Flow of blood (oxygenated)

A - Apex

B - Base

C - Right atrium

D - Left atrium

E - Right ventricle

F - Left ventricle

G - Aorta

H - Pulmonary trunk

Identify the parts 

A - Interventricular septum

B - Right ventricle (wall thickness)

C - Left ventricle (wall thickness)

D - Papillary muscles

E - Chordae tendineae

Inner parts of the heart

Broken heart syndrome

• happens when extreme stress suddenly weakens the heart muscles.

• The left ventricle balloon or “stuns” making it hard for the heart to pump blood 

• It mimics a heart attack with chest pain, shortness of breath, and irregular heartbeat.

• No arteries are blocked stress

  hormones temporarily disrupt heart

  function.

• Most people recover fully, but in rare

  cases it can lead to heart failure or death.

1. Single circulation

2. Double circulation

Types of circulation

Single circulation

• Blood goes through the heart once before reaching the body

• Example: Heart → Gills → Body → Heart

• Found in fish

Double circulation

• Blood goes through the heart twice in one full cycle

• Advantage: more efficient, delivers oxygen faster and in larger amounts

• Found in amphibians, reptiles, birds, mammals

Pulmonary circuit

carries blood to the lungs or gills

systemic circuit

carries blood to the rest of the body

Direction of blood: Away from the heart

function: Carry blood under high pressure

wall thickness: Thick, muscular

lumen size: Narrow

special features: Can handle high pressure; no valves (except aorta/pulmonary)

Direction of blood, function, wall thickness, lumen size, special features of Arteries

Direction of blood: Toward the heart

function: Return blood to the heart

wall thickness: Thin, less muscular

lumen size: Wide

special features: Have valves to prevent backflow; lower pressure

Direction of blood, function, wall thickness, lumen size, special features of Veins

Direction of blood: Between arteries and veins

function: Exchange of gases, nutrients, waste

wall thickness: Very thin (1 cell thick)

lumen size: Very small

special features: Site of diffusion; one cell can pass at a time

Direction of blood, function, wall thickness, lumen size, special features of capillaries

its an optical trick of light and skin. skin absorbs longer red wavelengths and reflects shorter blue wavelengths

why veins look blue, but your blood never is

blood

• fluid connective tissue

• made of cell and plasma

• flows through blood vessels

• main job: transport

1. Plasma

2. Red blood cells (RBCs)

3. White blood cells

4. Platelets

Components if blood

Plasma

55% of blood, mostly water, carries nutrients, hormones, and waste

Red Blood Cells (RBCs)

carry oxygen with hemoglobin

White Blood Cells (WBCs)

fight infections

Platelets

help blood clot to stop bleeding

Plasma

• Straw colored liquid

• 90% water, 10% dissolved

• Carries: nutrients, gases, hormones, wastes

• Helps maintain blood pressure and pH balance

Red blood cells

• Shape: biconcave disc → more surface area for oxygen

• Contains: hemoglobin → binds oxygen

• lifespan - 120 days

• No nucleus → can carry more oxygen

White blood cells

• Protect the body from bacteria, viruses, and parasites

• Types: Neutrophilis, lymphocytes, monocytes, eosinophiles, basophils

• some produce antibodies

• part of the immune system

Platelets

• Tiny cell fragments

• Help form clots to stop bleeding

• Work with fibrin to seal wounds

• Life span: 5-10 days

Blood under a microscope

antibodies

acts like a flag

Gravity pulls your blood down when you stand up

Why do you get dizzy when you stand up too fast. If your blood vessels and valves don't push it back to your brain fast enough, your brain gets less blood for a moment, making you feel dizzy or lightheaded.

• 2-Chambered heart

• Has 1 atrium and 1 ventricle

• Uses single circulation

• Blood path: body heart gills body

• Works well for animals living in water

• Heart pumps blood at lower pressure

Circulatory system for fishes

• 3-Chambered heart

• 2 atria and 1 ventricle

• No septum

• Uses double circulation

• Some mixing of oxygenated and deoxygenated blood

• Can use lungs and skin for breathing

• Good for life both in water and on land

circulatory system for amphibians

• Partially divided 3 chambers 

• Still has 2 atria

• Ventricle is partially divided

• Less mixinf of blood compared to amphibians

• More efficient for terrestrial life

• Crocodiles have a true 4-chambered heart

Circulatory system for reptiles

• 4-Chambered heart

• 2 atria + 2 ventricles

• Complete separation of blood

• Very strong and fast heartbeat

• Supports flight, which needs high oxygen

• Among the most efficient hearts

Circulatory system for birds

Fish: 2 chambers, single circulation

Amphibians: 3 chambers, mixing occurs

Reptiles: 3-4 chambers, partial separation

Birds: 4 chambers, very efficient

Mammals: 4 chambers, highest efficiency

Chambers for Fish, Amphibians, Reptiles, Birds, Mammals

Nervous system

Nervous System

• body's control and communication system

• detects internal and external stimuli

• coordinates responses and movements maintains homeostasis (temperature, heartbeat, digestion)

• includes brain, spinal cord, and nerves

Components: Brain and spinal cord

Function: Processes and integrates information

Control: Directs body activities

Protection: Protected by skull and vertebrae; surrounded. by cerebrospinal fluid

Components, Function, Control, Protection for the central nervous system (CNS) 

Components: All nerves outside the CNS

Function: Carries messages to and from the CNS

Control: Connects CNS to muscles, organs, and senses

Protection: No bony protection; vulnerable but supported by connective tissue

Components, Function, Control, Protection for the Peripheral Nervous System (PNS)

Neurons 

• Nerve cell

• has dendrites (receive info)

• has axon (sends info)

• signals travel as electrical impulses

Dendrites → Cell Body → Axon → Axon Terminals → Synapse → Next Neuron

Pathway of a Nerve Impulse

Most neurons don't reproduce and usually last a lifetime, unlike other cells in your body. However, some areas like the hippocampus can make a few new neurons through neurogenesis.

Do your brain cells ever get replaced, or are you stuck with the ones you're born with?

A mild bump to the head usually doesn't kill neurons or make someone less smart. However, strong or repeated blows can damage brain tissue and cause neuron loss, which may affect memory, thinking, or coordination.

If someone gets hit on the head, do their neurons die and make them less smart?

Forebrain, Midbrain, Hindbrain 

Parts of the brain

Forebrain 

thinking, smell, memory

Midbrain

vision, hearing, reflexes

Hindbrain

movement, balance, heartbeat

Forebrain (Prosencephalon)

• Small in fish, larger in amphibians, reptiles, birds, and largest in mammals

• More developed forebrain = higher intelligence and complex behavior

Cerebrum, Olfactory bulbs, Thalamus, Hypothalamus

Components of forebrain

Cerebrum

Controls thinking, decision-making, movements

Olfactory bulbs

Detect smells, important for finding food and sensing environment

Thalamus

Relays sensory signals to the cerebrum and regulates consciousness

Hypothalamus

Controls hunger, thirst, body temperature, and hormone release

Midbrain (Mesencephalon)

• Large in fish and amphibians for swimming/jumping

• In birds and mammals, mainly relays sensory information to the forebrain

Tectum, Tegmentum

Components of Midbrain

Tectum

Processes vision and hearing, helps animals react quickly

Tegmentum

Coordinates movement and reflexes

Hindbrain (Rhombencephalon)

• Coordinates basic posture and reflexes

• Essential for survival in all vertebrates

Medulla oblongata, Pons, Cerebellum (little brain)

Components for Hindbrain

Medulla oblongata

Controls heartbeat, breathing, digestion

Pons

Relays signals between brain and spinal cord, assists movement coordination

Cerebellum (little brain)

Controls balance, posture, and fine movements

Brainrot 

• is a temporary decline in brain efficiency caused by overstimulation or too much screen time.

• is functional, not structural-neurons are not dying

• High-dopamine activities like social media or binge-watching can lead to cognitive fatigue.

Nerves

bundles of neurons

Ganglia

clusters of nerve cell bodies

Peripheral nerves

link CNS to senses and muscles

ganglia

Simple animals rely more on _____ than brain

bigger brains and specialized nerve

More complex animals have _____

1. Olfactory (I) - Smell 

2. Optic (II) - vision

3. Oculomotor (III) - eye movement

4. Trochlear (IV) - eye muscle control

5. Trigeminal (V) - face sensation & chewing

6. Abducens (VI) - lateral eye movement

7. Facial (VII) - facial expression & taste

8. Vestibulocochlear (VIII) - hearing & balance

9. Glossopharyngeal (IX) - taste & swallowing

10. Vagus (X) - organs of chest & abdomen

11. Accessory (XI) - neck & shoulder muscles

12. Hypoglossal (XII) - tongue movement

Major Cranial Nerves

Olfactory (I)

Smell

Optic (II)

Vision

Oculomotor (III)

eye movement

Trochlear (IV)

eye muscle control

Trigeminal (V)

face sensation & chewing

Abducens (VI)

lateral eye movement

Facial (VII)

facial expression & taste

Vestibulocochlear (VIII)

hearing & balance

Glossopharyngeal (IX)

taste & swallowing

Vagus (X)

organs of chest & abdomen

Accessory (XI)

neck & shoulder muscles

Hypoglossal (XII)

tongue movement

• Brain: small forebrain, prominent midbrain

• Cerebellum controls swimming and balance

• Large optic lobes for vision underwater

• Lateral line system detects vibrations and water movement

Fish Nervous System

• Brain larger than fish, forebrain growing

• Cerebellum handles movement on land and water

• Can process more sensory info

• Nervous system adapted for dual habitat (water + land)

Amphibian Nervous System

• Bigger forebrain for more complex behavior

• More developed cerebrum for better behavior and learning 

• Cerebellum well-developed for movement on land Spinal cord controls limbs and body posture

• Some possess Jacobson's organ for chemical sensing

Reptile Nervous System

• Large forebrain and cerebellum

• Excellent vision and coordination for flight

• Well-developed optic lobes excellent vision

• High neuron density → fast processing Complex behaviors: communication, migration

Bird Nervous System

Brains with more folds-called gyri and sulci-have more surface area, which allows for more neurons and connections. More neurons and connections mean the brain can process information faster, store more memory, and solve complex problems. However, intelligence isn't just about folds-genes, experience, and learning also matter.

Does a brain with more folds make a person more intelligent? Why or why not?

• Trend: small → medium  → large forebrain

• Cortex folds increase → more surface area, more intelligence (seen in mammals)

• Evolution favors brains that match the environment no "perfect brain," only "best for survival"

• Complexity matches lifestyle and environment

Brain Evolution