Regulation of Cardiac Activity
❤️ How the Heart Controls Itself (Intrinsic Regulation)
The heart regulates its own activity automatically through special muscles called nodal tissue! This is why we call it myogenic (muscle-originated).
🧠 How the Brain Helps (Extrinsic Regulation)
A special control center in the medulla oblongata (base of your brain) fine-tunes heart function through nerves:
- 🚀 Sympathetic nerves: Speed up heartbeat 💓, make ventricles squeeze harder → increase blood pumped out.
- 🐢 Parasympathetic nerves: Slow down heartbeat, reduce signal speed → decrease blood pumped out.
🔥 Hormonal Boost
Hormones from your adrenal glands (like adrenaline) can also increase heart output when you’re excited or scared!
Disorders of Circulatory System
⚠️ High Blood Pressure (Hypertension)
Blood pressure higher than normal 120/80 mmHg is called hypertension. Let’s break this down:
- 120 mmHg = Systolic pressure (heart pumping pressure) ⚡
- 80 mmHg = Diastolic pressure (heart resting pressure) 💤
🚨 Diagnosis: If someone’s blood pressure is repeatedly 140/90 or higher, it’s considered hypertension.
🌟 NEET Super-Important Concepts 🌟
These topics appear frequently:
- Myogenic heart regulation (nodal tissue role)
- Sympathetic vs. Parasympathetic effects on heart rate & output
- Hypertension thresholds (120/80 normal vs. 140/90 hypertensive)
- Role of medulla oblongata in heart control
- How adrenal hormones boost cardiac output
Remember these for your exam! 👍
