SAAT Biology Section 5.2 Vocabulary (Human Biology) - تحصيلي

Central nervous system (CNS)

Composed of the brain and spinal cord

Brain

Control center of the body

Cerebrum

Largest part of the brain that is divided into two hemispheres which are connected by corpus callosum

Cerebrum responsibility

Learning, memory, language, speech, coluntary body movements, and sensory perception

Corpus callosum

The brain's largest bundle of white matter, consisting of 200–300 million axons that bridge the left and right hemispheres

Cerebellum

Controls ballance, posture, and coordination (located at the lower back of the brain)

Cerebellum responsibility

For the smooth and coordinated movement of skeletal muscles and is also involved with some motore skills (such as playing the pianp or riding a bike or typing on a computer)

Medulla oblongata

Relays signals between the brain and the spinal cord (also helps control breathing rate, heart rate, and blood pressure)

Pons

Relays signals between the cerebrum and the cerebellum (also help control the rate of breathing)

Hypothalamus

Regulates body temperature, thirst, appetite, and water balance (regulatres blood pressure, sleep, aggression, fear, and sexual desire)

Where the reflexes are

Pocessed in the spinal cord

Peripheral nervous system (PNS)

Consists of the snsory neurons and motor neurons that carry information to and from the CNS

Number of cranial nerves

12

Number of spinal nerves

31

Automatic nervous system

Carries impulses from the central nervous system to the heart and other internal organs

Automatic nervous system responsibility

Body’s involuntary responses

Automatic nervous system used in situations

Fight-or-flight responses which activates the sympathetic NS and in normal state when your body is resting (digests activating parasympathetic NS)

Iris (eye muscle) sympathetic stimulation

Pupil dilation

Iris (eye muscle) parashympathetic stimulation

Pupil constriction

Salivary glands sympathetic stimulation

Saliva production reduced

Salivary glands parasympathetic stimulation

Saliva production increased

Oral/nasal mucosa sympathetic stimulation

Mucus production reduced

Oral/nasal mucosa parasympathetic stimulation

Mucus production increased

Heart sympathetic stimulation

Heart rate and force increased

Heart parasympathetic stimulation

Heart rate and force decreased

Lung sympathetic stimulation

Bronchial muscle relaxed

Lung parasympathetic stimulation

Bronchial muscle contracted

Stomach sympathetic stimulation

Muscle contractions reduced

Stomach parasympathetic stimulation

Gastric juice secreted, motility increased

Small intestine sympathetic stimulation

Muscle contractions reduced (small)

Small intestine parasympathetic stimulation

Digestion increased

Large intestine sympathetic stimulation

Muscle contractions reduced (large)

Large intestine parasympathetic stimulation

Secretions and motility increased

Drug

Substance, natural or artificial, that alters the functions of the body

A drug can cause an increase in

The amount of neruotransmitters that are released into the synapse

A drug can block

A receptor site on a dendrite, preventing a nerotransmitter from binding

A drug can prevent

A neurotransmitter from leaving a synpase

A drug can also imitate

A neurotransmitter

Stimulants

Drugs that increase alertness and physical activity

Nicotine

In a cigarette or cigar smoke that increases the amount of dopamine released into a synapse

Caffeine

Works by binding to adenosine receptors on neurons in the brain

Example of stimulants

Cocaine and methamphatemine

Depressants

Drugs that tend to slow down the central nervous system

Example of depressants

Heroine, morphine, and alcohol

What depressants can do

Lower blood pressure, interrupt breathing, and slow the heart rate

When independence or tolerance takes place

When a person is in need for more drugs to feel satisfied; this will make them increase the dose and will lead to addiction

Addiction

Psychological and physiological dependence on a drug

Dopamine

A neurostransmitter found in the brain that is involved with the control of the body movements and pleasure

Circulatory system

An organ system that permits blood to circulate and transport nutrients, ocygen, carbon dioxide, hormones, and blood vessels, to and from for homeostasis

What the circulatory system consists of

Blood vessels, the heart, blood, and the lymphatic system

Arteries

Type of blood vessel that carries oxyenated blood away from the heart (they have solid, elastic, and thick walls and can tolerate the high pressure of the blood that is pumped by the heart)

Veins

Type of blood vessel that carries deoxygenated blood to the heart

The pressure of the blood decreases when

The blood flows through capillaries before it enters the veins

Valves

Flaps of tissue that prevent blood from flowing back (only large veins have this)

Capillaries

Microscopic blood vessels where the exchange of important substances and waste occur

Capillaries’ walls

Only one cell thick, this permits the easy exchange of materials between the blood and tissues by diffusion and filteration